I’m not sure it even makes sense to review Xcode as an app. If you want to write software for the Mac (or the iPhone), you pretty much have to use it.
There’s a lot to love. Interface Builder is the best of its kind, and the constraint system works very well now. The nib system is clever, and as modern xibs, it’s feasible to use with version control. The profiler is among the best I’ve seen. Keyboard navigation is surprisingly good. It integrates with Git these days (more or less).
There’s a lot to hate. The line spacing bounces around for no apparent reason. It still crashes too often. Autocomplete is slow and unreliable. The Swift compiler still feels like a beta, in all respects, even at version 3.0. The text editor is not particularly powerful.
But is anybody going to use or not use Xcode, based on a review? Nope. Install it, do the best you can with it, and file bug reports whenever you run into trouble.