Yes, it's brilliant (Ubuntu here) and felt less of a chore to install than compiz (though I did that a while ago on FC5). Do note the customistation aspect of it, as saffyre posted. The default configuration is a bit 'generous' in the effects it uses and is more of an example of what it can do than a usable configuration.
Tone down the magnitude of the effects, disable things you don't need, change the animations to quick-fades, disable water effects and so on. With a bit of tweaking it really works as it should- clean, unobtrusively and exactly to your taste.
Running it on an X1800/A64 3700+ with no issues and no noticeable slowdown. The only issue is getting XGL and the ATI drivers to play ball. Not got that running stable yet.