Fantastic Tool!!! I use it every day together with the desktop version. Sync is done with iDISK.

The BEST task manager available on the iPhone! Fully embodies the GTD concepts & leverages the location framework to find contexts you can act on where you are. Recent updates have vastly improved syncing time.

Not the cheapest iPhone OS app, but well worth the money if you value your time. Get the desktop app for your Mac for the ultimate productivity boost.

Excellent app. Feature-rich with a clean interface and very logical structure. Hence easy to learn and intuitive to maneuver. Flawless sync with Mac desktop app via MobileMe, Bonjour, etc. Solid company behind this app. Developer delivers on promises. Continuous update policy. Responsive and competent support ever since. This app has soul (google kGTD...) and heart - it's nothing but excellent.

I'll agree with the other commenters, fantastic app, shows much promise, a very good 1.0 offering. Of course, that sets the stage for future improvement, and I've sent them my feature requests and redesign suggestions:

1. Adding contacts to Contexts — while it's nice to add a contact to the location of a Context, it's currently not a very person-centric way of doing things. You're linking a contact because you want to contact them. It would be great if, when linking a contact, it would also put that person's main phone number (or whichever number, chosen via a sheet) in an easily-clickable button. Since one of the default contexts is People:Boss, it'd be nice to attach the boss's location and phone number to that context. And that location/phone number should cascade to all actions using that Context. This would make things easier if you change bosses: change the contact in your Context, and your actions get changed too.

2. Clickable location in action item — If the item's assigned Context has a location, it should cascade to the Action, and it should be clickable, bringing you out to the Google Maps app. As I mentioned above, the same should be true of phone number, if there's a contact linked to the Context.

3. Import Inbox Actions from TaDa List  — it would be really stellar to be able to import action items from an online service like 37 Signals' TaDa List. No password needed, just supply the URL, and the new to-do items are added to the Inbox, without Context. This makes it easy to have a "virtual drop box" online. For example, a family keeps their shopping list on TaDa List, and whoever will be near the store can pull the list down into their Inbox, and check items off (or delete them).

At the present this is the best task manager, by far. It is the only one ready for prime time. Things has promise, but they are still months from having something like Omnifocus. If you need a serious app for managing your work, this is it. Well worth the money and the learning effort. You will like it if you need an app like this one. If you do not need it, it may result a bit excesive for you. This is not a simple to do list app.
The desktop version is a bit expensive though. The Omnigroup support is excellent, so it may be worth it.

The actual version is pretty good, but it is not perfect. There are a few issues that may be improved. The startup is a bit slow but it is improving (now 3-4 secs for me while loading the database with version 1.0.2). This may be a problem if you need to do a quick entry. At the present it does not support perspectives like the desktop app does (preset views of your tasks filtered in different ways). The sync with MobileMe can be a tad slow too. There is a bug that is being ironed out.

Definitely the best todo app for the mac/iphone person. If you are serious about having a digital tool to help manage a complex life, this is worth the time and money to acquire and learn.

Nice UI - well thought out, and the synchronization works (with a beta of the desktop OmniFocus). My only real issues are the price of the desktop application and the slow startup time of the iPhone app.

Well worth the money, if not for the location feature alone. Create a list for home, list for office, list for different stores, and when you are in those locations it moves those lists to the top. Keeps even the busiest of lifestyles all neat and organized with minimum effort.