Maintaining two CentOS servers and "using" Linux Mint on my notebook as a secondary OS (very, veeeery rarely though, since I installed it mostly because of the MadWiFi drivers for WiFi network analysis and probing).
Window manager of choice? Gnome or FluxBox.
Compiz? Sure, why not, but only limited to basic minmize effects + expose. Anything else is "cool" only for the first 15 seconds.
Why I rarely use it? The primary reason is the presence of s**tloads of driver problems - can't resume after stand by, sound driver sucks - I can barely hear anything at 90% volume, but 95% rocks my socks off from all the loudness, installing wireless drivers is a pain in the neck, shortened battery life, etc. There are other things that I hate about it, but still, LinuxMint is the best distro out there for the average Joe, since it actually takes a shot at depressing the dreaded console back behind the scenes, and succeeds in doing so in some parts of the OS. Would recommend.