>>1
I'm not sure. I really liked it when I tried it (OSXfag here). Lots of tweaks ance nice things, plus it's kind of retarded not to be running in a GPU-accelerated windowing environment in 2006\2007.
If you have concerns over using every little part of every little resource available in your computer with the highest possible efficiency, it's obviously not the best idea, same if you're obsessed with security concerns or stability. But if you want a better OS, I'd say now's a fine time to try it out, the final feels pretty good to me, plus it's so much better organised with some decent inbuilt apps that feel very OS X-ey (calendar, photo gallery, even mail).
>>3
lol ram. Used about as much as I'd expect when I tried it - heaven forbid a modern OS actually recognises the fact most people would prefer a more responsive interface with more useful features than have much of their 512mb-2gb of RAM avaiable sitting around doing nothing. Go back to coding your unix command line in assembly.