I'm using LinuxPPC, doublebooting with MacOS, on an iMac. I love my Linux box very much (the OS takes up hardly any room (so I can play Quake3!); code compiles screamingly fast); however, I wouldn't reccomend it for people who want their machines to be a black box (or beige box). You do have to learn about what's really going on, instead of just pointing and clicking. There aren't ports of many popular software apps, although there's all kinds of stuff showing up on Freshmeat all the time. I suppose it is possible to run Linux as a user from an Xwindows GUI without ever having to go into command-line, but that takes all the fun out of it!