You can use JetBrain's AppCode if you dislike (despise) Xcode :) It's written in Java, but at least it doesn't crash every couple of days (possibly corrupting(!) .xcodeproject files).

And the Modern ObjC (with ARC, @properties, blocks, new @literals, awesome and useful clang errors, etc.) is much, much better than it was around iPhone OS 3.0! The signal/noise ratio of a typical iOS app is now maybe twice that of an app written in the bad old days.

I use vim for writing code, and the IDE for a couple tasks like running the simulator.