How does this project compare to the three320 project originally started by Joe Hewitt from Facebook? 320 seems to have more features:
The 320 devs appear to still be on Xcode3, and demand a bunch of nonstandard settings on Xcode4 to make it work (including a scary script which edits your project in all sorts of ways).
He realized that Three20 was becoming pretty bloated and outdated and created this spinoff project.
I'd say both this and Three20 are pretty bloated and dated. They are both great reference projects to see how things could be done but in general there are a lot more lightweight alternatives out there.