Well this is a great app… Just a comment, after reading the discussion here about OmniFocus and alternatives, regarding "learning curve", "complicated", etc. etc. etc. – not everybody needs an app like OmniFocus. If you do only errands and your "projects" are things like buying Christmas presents or cleaning up the attic, then OmniFocus probably feels bloated to you and it really is a waste of time and money and you should get another, simpler app.

However, if you work as a freelancer, in the creative business, as a scientist – then you've probably made the experience that sometimes one has to neglect errands to focus on large projects (focussing is about saying "no", a wise man said). The usual to-do-apps are potentially dangerous, because they are especially good at errands, and this can lead to procrastination – instead of working on the "big" project, one does just some errands, goes through the to-do-list and has the feeling of "wow, I am productive!", while actually, one isn't touching the really important, harder (because more complicated) work.

For managing multiple larger projects OmniFocus proved immensely helpful to me. The key is to split up the projects into smaller tasks, sub-tasks, sub-sub-tasks, because these are easier to approach – this way you don't lose oversight nor run danger of getting blockades (and going back to your to-do-list-procrastination-routine). OmniFocus allows for a maximum of flexibility for splitting up tasks, and offers a clean view with its "outline-like"-layout. The limitation of being able to add only one context is actually a very good thing: if you have more than one context, most probably you should split up your task into sub-tasks.

Now some may think it is a waste to spend that much time planing tasks. But for me this helps to decide what tasks are most important and which I can do later (=never). Usually it's the errands that allow for being late or even simply not doing them (well, not a good strategy for paying your taxes of course). Having oversight over your tasks helps freeing up blockades – only that makes research/inventive work possible.

For my needs, OmniFocus really isn't too complicated or bloated. Actually quite the opposite, it's cleanly designed and if anything, it could offer some more features (more options for perspective building)… And well, yes, one has to mention it: OmniFocus never crashes, you never lose data, it's just rock stable.

Version 2 is scheduled for end of this month, by the way…

Just a heads-up: It would appear that the price of OmniFocus, for both MAS and direct download versions, has returned to $79.99.

I own it. The price is competitive finally. That was a big part of why I bought it - and the fact that I like OmniOutliner, having used it for a decade.

Frankly, its a little restrictive to use OmniFocus, in my mind.

OmniOutliner would require more set-up, but is more versatile in a lot of ways, though OF is still good & has some built-in tracking modalities that OmniOutliner could not handle as well.

I think it could use a make-over to be more useful.

I use a lot of GTD tools, but its hard to stick to them or dwell in an environment that meshes well.

When I want to write something down - I don't want to futz around with database creation or to think how to design the recording framework in the midst of an idea or when a task needs to be listed.

This gets you past that quite well.
Although not all the way home if there are more complicated actions or procedures to eventually nuance a task.

Price is currently 39.99$

I tested different programs like Things (nice and clean interface) and The Hit List (superb input methods) to see which one would fit my personal task organizing needs. Neither did.

When I tried OmniFocus its interface looked quite complex and seemed to lack some polish at first, but after some time I realized how mighty and well-thought-out it this program is.
I don't use the GTD methodology but a different approach. Nevertheless OmniFocus is perfectly able to handle it (- unlike Things and THL).
IMHO its flexibility is the reason why it's the superior task organizing tool for Mac: I can group tasks into different folders (in my case these are my different "roles" in life) and create endlessly nested subtasks (breaking down big tasks into manageable pieces). Contexts allow to further refine the task structure. Different "views" can be configured, saved and reused in order to quickly gain the perfect overview in different situations.
The syncing with the iPhone App works flawlessly, smoothly and reliably.
For me this app is almost perfect and really helps me to keep up with a bunch of different tasks and duties using my own methods.

The only thing I'm still missing is the possibility to create subtasks within subtasks using the iPhone app. It can show and edit those nested subtasks, but I have to create the nested structure on the desktop app. But that's rather a concern with the iPhone app than with the desktop app.

All in all I love this program. Yes, it is relatively expensive but its flexibility makes up for it. It really helped me to increase my productivity.