KILLERBEEZ   The Demo version is a waste of time and useless. It is $35.00 to test this product.  
(Version 1.7.2)

PUSFARM  The demo only works on 100MB and smaller drives?? So anyone, like me, who doesn't still have a drive left over from 1997 is basically screwed. That makes this demo useless to me. Coincidentally, it also means it doesn't get purchased.  
(Version 1.7.2)

RRNOWELL  Their iPartition product comes with iDefrag Lite. The full version of iDefrag adds the following: Online Defragmentation, Optimization, Full Defrag, and Jump to File by Name of ID.

I like this company. They seem straight forward and up front. This is refreshing. I suspect the company is still run by developers and not bean counters and marketeers who have lost touch with integrity and customer service and a love of producing a product one can be proud of and feel good about.

Even though I have purchased the product it is too early to give a new user review as I need to use it more and get a feel for how the customer is handled.

A full list of the features of each taken from the iDefrag help menu Overview is listed below:

Key Features

Feature iDefrag Lite iDefrag

=======================================

Supported Filesystems

HFS (Mac OS Standard) x x

HFS+ (Mac OS Extended) x x

HFS+ (Mac OS Journaled) x x

HFSX (Mac OS Case Sensitive) x x

Defragmentation

Metadata Defrag/Tidy x x

Compaction x x

On-line Defragmentation x

Optimization x

Full Defrag x

User Interface

Per-block Display x x

Whole Disk Display x x

File Information x x

Class-based Data Coloring x x

Jump to File by Name or ID x

Asynchronous Operation x x

Other

AppleScript Support x x

Advanced Classification System x x

Metadata Zone (“Hot Zone”) Support x x

Adaptive Hot File Clustering Support x x

Built-in Bug Reporter x x

MacPAD-based Auto-update System x x

Altivec Accelerated Display x x  
(Version 1.7.2)

ALASTAIR (CORIOLIS SYSTEMS)  The version 2.0 beta that is available to some customers on our site is *NOT* "released to the public" and shouldn't be being reviewed here as it's generating significant confusion. I've just spent a significant number of hours answering queries about the purported "release" of version 2, which simply HAS NOT HAPPENED.  
(Version 2.0.0b2)

OFFLINE  I need to test it a bit more. My machine halted while doing an on-line default defragmentation of an external hard drive.

First time that happened with iDefrag software. I understand it's a beta; however, because it's released to the public, I have to give it a poor rating.

I've given final releases of their other products 5 stars (for comparison purposes).  
(Version 2.0.0b2)

MAC ADAM  I wait fot a version 2 a complete interface rebuild Leopard Style, and still stable at less like today (1.7.2). Thanks for this great app ;)  
(Version 2.0.0b2)

WABES2K  Also, someone commented earlier that after defragmenting their hard drive with iDefrag, Time Machine backed up all their data as if it was all new. I have not had this issue with either version 1.x or 2.0 beta.  
(Version 2.0.0b2)

WABES2K  Version 2 looks really nice! In the old version, I always had to burn a bootable disc to run a full defrag on my startup disk. I did this each time because there would be an update to the app by the time I defragmented my hard drive again. In the new version, that is still an option, but is no longer necessary. When you run a full defrag on your startup disk, iDefrag simply restarts your Mac into a special mode so that it is the only app controlling the hard drive. I'm looking forward to getting version 2 when it comes out!

I ran into an error telling me I had insufficient movable free space, when in fact I had 86GB of free space. Turns out I had an error on my drive (which was not the fault of iDefrag). I just had to run repair disk (available from the "check for errors" menu option in iDefrag) to fix it before I could finish defragmenting my drive. I initially submitted this as a bug report, and I can say that their support staff were very prompt with their replies and helpful.

There is a lot of differing opinion about whether a Mac HD needs to be defragmented, but I definitely like to do this once every several months. Whenever my Mac gets pretty sluggish, I know its time to defragment my HD. My apps really are much snappier afterward. As much time and frustration as its saved me, it is definitely worth the money.  
(Version 2.0.0b2)

GARY54  I've used this program since I stated using X. Make that about 4 years? Since 10.3? Excellent meat and potatoes program. It does what its supposed to do, doesn't try to do everything under the sun and walk the dog too and its been regularly updated.

It has a good feature set, provides good feedback information about what its doing and the files on your disk. I've used that to clear out gigs of useless junk hiding *what the hell is THAT huge file?*. There is a observable speed up of the system particularly after the first time using it and I would not hesitate to recommend it.

I have always used DW before running a defrag to be sure of the directory being clean ... that only takes a few minutes ...and after to make sure there are no errors after. Cheap insurance which takes but a few more minutes of time.

I have one major complaint about this program. It's .... slow. And I do mean .. slow. Like .. molasses in January kind of slow. If I have a drive with a lot of stuff on it, I set it up to run before going to bed. Most of the time it's done by the time I get up. A few times not.  
(Version 1.7.2)

REDDOG99  Correction to my previous comment: The RAID volume is grayed out, but a defrag is still possible. As a long time user of iDefrag, I'm very satisfied. The program works well and customer support is excellent.  
(Version 1.7.2)