Things is nice but it really and truly does feel like development there has majorly stagnated. They are providing small, incremental updates for various features, but we've been waiting on the "coming soon" push notifications support in Things for iPhone for a year now with no real changes beyond delays.
The lack of over-the-air syncing is really a big pain! GTD apps are suppose to empty your brain of unnecessary things but I still have to remember to sync.
I can't make a conclusion for everyone out there - this really is like asking what car you should drive. That said I did make it clear in the post that it is OmniFocus for me all the way.
I have a strange relationship with OmniFocus. I hate thinking about using it, but when I do use it I don't mind it. The Mac version is decent, but the slow startup time of the iPhone app really destroys its utility for me.
That said, after plunking down $80 for the desktop version that I use but hate thinking about, $20 for an iPhone version I never use, I just can't bring myself to spending $40 for the iPad version without being able to figure out if I'll actually use it first (I understand this is more a criticism of the App Store rules than of OmniFocus specifically).
If it helps, I've actually ditched the desktop version in favor of the iPad client, except in the limited case of moving tasks from e-mail to OF. Everything else I do on the iPad client now.
It's fantastic. Forecast view is probably one of the best things to ever happen to me.
I used to prefer OmniFocus, but I've lost enough data using it that I have switched entirely to Things. Makes me sad as I am a huge fan of OmniOutliner.
If you'd rather use a webapp, I've been using Nirvana (http://nirvanahq.com) -- basically Things in the browser -- pretty happily for the past couple of weeks.
I was previously a Remember The Milk-er, but was never 100% satisfied with it. Nirvana suits my organizational style much better.
I have owned and used pretty much every single GTD app on the market.
OmniFocus has been the winner for me simply due to its maturity. I use it in conjunction with org-mode for Emacs. org-mode is what I use for managing my code and computing environment. OmniFocus is bigger picture: "Call so-and-so @Phone"
I have to also drop my hat in the ring for TaskPaper. It's quite well done.
However, OmniFocus is unfortunate in the sense that you cannot export a flat file. It also is unfortunate how big of a behemoth the iPhone application is. I wish they'd include a standalone quick entry application so I don't have to load the entire database every single time I use the app.
I just want a client that works with org-mode. I have that for iPhone, but not quite for iPad or Android just yet. That's where it gets universal for me.
Yeah, mobileorg is decent on the iPhone, but iPhone apps on the iPad are just useless. I basically don't do it and hope it gets updated before I get too frustrated and try to get involved. :)
There's a good version for iPhone that runs on the iPad (though not really in any way I'd want to). There's also an Android version, but it doesn't support dropbox.
