I have to agree that the latest Xcode 4.2 and iOS 5 has been nothing but painful for me. Xcode 4.2 seems really unstable. Seems like every 5th or so build that I'm doing, it seems to hang, which throws me for a loop on trying to find out whether it's my code or Xcode. More often than not, it's been Xcode.
iOS5 may be good in the longer term, but in the past week, I've had to spend a lot of time just tweaking my apps to be 'iOS 5 compatible'. Not a very productive period for me.
I want my Xcode 3.2.6 back...

... but I guess we just have to get used to this new stuff and press forward.