Root is very simple, the application of the custom recover console and the creation of nandroid backups (and applying them) is tougher. Installing an actual ROM is more involved as well. DM updater will do these things for you, but I found "Droidreview's" youtube instruction videos to be very educational and they will teach you more about what is going on than just letting an app do the work for you. Some of the instructions will differ slightly if you are appling a xxxxxx.rom.tgz file rather than expanding your own. By the time you get to that stage you'll know what I mean.
I had no root or linux knowledge and rooted yesterday. I applied SPRecovery, tried out a couple of roms, overclocked, reapplied my 2.0.1 backup, and then full wiped the phone all the way back to stock as if I'd just purchased it. Cool stuff!
Live wall papers, 2.1 launcher and 2.1 media dock were my favorites. I didn't notice a smoother experience though, even with the phone overclocked to 800Mhz. I had quite a few force closes and 5-6 restarts. I believe I would have better luck now since I had not performed any full wipes between ROMs.