It's night and I'm sleepy, so this will be short. I've replaced ubuntu with gentoo on my laptop. I have to say that gentoo is a pleasant surprise. No behind-the-scenes "magic" - you have to do everything by yourself. All important aspects of the system are well documented. Compiling stuff is not that of a chore with the emerge - their packaging system. I also like the non-SYSV init because close to BSD-style init.
I also have to say that I have a very good experience with their support. The only package that failed to compile was bochs. I decided to report the bug and received an answer within 15 minutes. Impressive.
So far - no frustrations and a feeling of a well-designed system that gives great freedom to its users.