LEV  In my reply to the previous poster I forgot to mention a couple of things which tilt the balance of power further towards Mellel over Pages '09.

First, a small but significant omission in Pages: you can't define the Outline Level of a paragraph style. Word has been able to do this for as long as I can remember and it's surprisingly useful. In Pages you have to (a) select every occurrence of the style you want to change, then re-assign it all to the pre-ordained Outline Level style. It's probably not that interesting for anyone doing a short document but for handling long docs, even relatively unstructured ones, it's nice to be able to kill the *visual* link between appearance and outline level while retaining the *structural* link.

Mellel's approach is quite different. The outline structure is in a different window (or "drawer", rather) and you can set it up so that the outline headings are actually invisible in the text itself. So headings enable you to keep an eye on your structure -- and move it all around at will -- while keeping the actual copy clean.

The other, and big, thing about Mellel which nothing else offers is the idea of Style Sets. I have one for on-screen work and one for printed work, for example. With literally one mouse-click you can change *everything* about a document's appearance while leaving the structure untouched. It's immensely powerful and very useful.

I believe the thing that confuses people about Mellel is that it adopts the sound engineering principle of front-end loading. That means you make your decisions about formatting etc. in advance, then save all those decisions -- paragraph and character styles, footnotes, auto-titling and everything -- as a style set which can be applied to any document, even retrospectively, with a minimum of effort.

For actual writing -- as opposed to collaborating with others -- Mellel remains unmatched. If the developers implement change tracking and commenting in a way compatible with Word (the awful golem lurching about the entire world of WP) then there'll be no reason ever to use anything else. But it's hard, because Mellel (a) takes such a different approach to structure -- it's more like LaTeX in that respect, though without the geekiness -- and (b) does so many things that can't be transferred to Word files because Word just can't do them.  
(Version 2.6)

BRUMM  My opinion on word processor for OS X:

The last days I've tested many word processors and I found Mellel to be the best so far,

Mellel is not bloated like all the "Office" suites (Neo, OO, MS, are all to slow, ... for me Neo Office is the best of these beasts.)

and Mellel is better than:

- Nisus (Nearest competitor but Nisus doesn't support soft hyphen!, I cannot work without soft hyphen.),

- Mariner Write (really bad font display/spacing for many years now, only english, carbon - so it needs to be rewritten for future OSX releases, will they do that? I'm unsure.)

- Pages (Again no soft hyphen!, occasionally crashes and after a while gets very slow, ... but I exspect the next versions will be much better)

- Papyrus (very ugly, carbon, no real testdrive possible - crippled trial version, but some interesting features - I keep an eye on it)

- AbiWord (Many bugs and no updates the last 2 years, I think they don't support the Mac anymore)

- Bean (really fanstatic freeware, based on Apples buggy text-engine. No soft hyphen! So only usable for some very short texts, best freeware I've seen for many many years - of course I keep an eye on it)

For now I will use Mellel.

The only things that I don't like are related to the interface design, for example the round beveled look of the ruler and tools section is very outdated now, a boring all-grey mix of alien spaceship ("aqua"-style) or early iTunes versions ("metal"-style).

But besides that Mellel has the best combination of features for me, so my money goes to them.  
(Version 2.5)

INYAR  I just finished my master's dissertation (in French) using Mellel. Mellel, in combination with Bookends for the bibliography, are the best things that helped me in writing my dissertation.

Among many great features and qualities, I'd like to underline some :

- Perfect stability : never crashed, frequent autosave... and not a single problem with a 140 pages document including PDF, images and tables.

- Power of autotitles for outlining and configuring titles format, including in the Table of Contents...

- Power of "Character styles", "Variations" and "Paragraph styles", and a lot of useful key shortcuts (F1->F8 for characters variations)

- Perfect integration with Bookends (and probably also with Sente and other bibliography softwares)

- Power of Search/Replace function, with regular expression, saving of search/replace templates and creation of search/replace sets. It saved me a couple of days of verification and correction.

I think Mellel is a must-have for writing all kinds of very regular/organized texts, like academic/scientific writing, novel writing, etc.  
(Version 2.2.7)

SKAERTUS  Mellel is the best word processor in any platform. Very fast, very stable, very low on system resources. It has lots of well-designed features, especially the ones suited for academic writing. Its cross-references feature is miles ahead of Microsoft Word (Apple Pages not even supports it...). Styles are great too.

I've found its interface to be quite intuitive, and the tutorial is simple to check for information when you need it. It is not similar to Microsoft Word, and that is why users may complain a little. However, I didn't find any difficulty in exploring all of its features.

Mellel is compatible with .DOC and .RTF files, but not fully compatible, especially because Mellel implements its features in a way completely different from Word and other standard word processors. However, you may import and export from .RTF and .DOC and, while the layout may get screwed up, the text structure is maintained.

I've found Mellel to be the fastest and most streamlined of all MacOS word processors. Nisus Writer Pro is great too, but Mellel is even better. It's more and more becoming a killer app on the MacOS.  
(Version 2.6.1)

EASER  I like this program, but I have a big issue with the constant hassle of having to convert between Mellel propriety format and MS Word format. If I open a Word document in Mellel and modify it, I cannot simply "save" the changes. I now have to export it in Word format as a new document. And then if I re-open that document and modify it again, I have to again export it as yet another Word document. How is this convenient? It simply adds clutter to my file system. I do not see why they cannot simply add a preference feature to allow documents to be saved in their current format. Nisus does this without a hitch.  
(Version 2.2.7.1)

LEV  A heads-up.

I've been an enthusiastic -- and satisfied! -- user of this excellent app since v1.

But a caveat for anyone thinking of using it with Leopard. So far, Mellel files are not being read by Spotlight, and don't play with QuickLook or CoverFlow.

No word (surprisingly) from the developers on when we can expect this. QuickLook & CoverFlow is manageable, but Spotlight invisibility is a real problem.

So I suggest if you're thinking of getting Mellel -- and it is, as I have said before, a very fine WP indeed -- either stick with Tiger or wait until the developers come out with the requisite plug-in.  
(Version 2.2.7.1)

BILLYFUSTER  With version 2.2 Mellel's bibliography and citation features are now top-rate. It integrates beautifully with Bookends 9.2 (also just updated and packing many great new features). Now Mellel lets you toggle back and forth between temporary citations and final-formatted citations. No more generating a 2nd document to format the citations.

2.2 also implements other highly requested features, styled auto-titles and highlighted text (aka 'markers'). They also managed to throw in a massive number of character-level options, such as character fill and dashed outlines.

The Redlers continue to add features but the application stays solid, scalable, and responsive.   
(Version 2.2)

EASER  I recently got involved in some rather intensive writing projects. My needs are fairly simple; I needed a fairly simple word processor. I own MS Word, but like many users, I find it to run slow and to crash unexpectedly (without retaining the saved information one would expect it to save). I literally tried every single word processing alternative I could find and settled on Mellel.

I would say the Nisus does the best job of importing Word documents and retaining their characteristics. But I've also found it fairly simple to just copy and paste from Word to Mellel. I've also found that when I export from Mellel into Word format and then open the document in Word, I have to modify some of the work I've done. And again, I find that Nisus probably does a better job in its exporting in this regard.

So, why do I choose Mellel? Several reasons. One, I like the Mellel interface. I find it elegant, and I like that when I'm writing for long periods of time. MS Word gives me eyestrain, even though I've customized the toolbars to my bare minimum needs.

Second, I find Mellel to simply feel smoother when I write. It's fast; it does not slow down my machine; and it has a certain stability that's reassuring. I realize these might not be the best criteria for choosing a word processor, but my user experience has been the happiest with this program. (Mellel has loads of other features that I don't understand in any word processor; I'll leave it to others to discuss those.)

The one thing I would like to see is the ability to customize the toolbar in Mellel. I'd like to have a save button, for example. The developers tell me this may be in the works. I'd also like to have the Nisus feature wherein I can choose a default save method. Rather than constantly exporting to a Word format, I'd like to be able to simply choose "Save" and it automatically saves in Word format.   
(Version 2.1.2)

VANGOCAMBO  I've been using this program for over 2 years now. It never let me down until I wrote my thesis, the requirement is to have underline under first header, i always set the under for the autotile and style. however everything i print, the underline become double underline. It is really frustrating. i ended up changing to word to edit manually there. Please take a look at the issue maybe if it already address, please show us how.  
(Version 2.7.1)

MACEDWARD  A good product made even better. This word processor has been my primary writing tool for the last couple of years and will probably continue to be so as far as I can tell.

I have tried them all (nearly) and so far Mellel have not let my down.   
(Version 2.6.1)