Yes. I often fall back to using AppCode to work on Objective-C projects.
  http://www.jetbrains.com/objc/

But I generally agree that Xcode is pretty coupled with development for iOS/Mac OSX projects. But as a cross-disciplined developer who often works on web as well as iOS projects, having the IDE behaving consistently is important to me to minimize context switching (muscle memories be damned). I first serious IDE was JetBrains IDEA, then when I learned Ruby, I started using RubyMine. And now that I'm working more and more with Objective-C/Swift, AppCode is often the IDE I use when I am not working with Interface Builder or configuring the project (which the latest version of AppCode is starting to allow you to do; and with the latest major update to Swift, it may take another 6mo-1yr for AppCode to catch up).