I'm also going to echo this- I've done only a bit of playing around with Ubuntu, but with mediatemple downtime issues I was having (grid service is not quite what they advertise) I decided to jump in and get a slice about 2 months ago.

I couldn't be happier. The tutorials (especially the ones for Ubuntu) are fantastic, and setting up your server and security with shorewall/etc couldn't be more painless. I probably took only an hour and had apache/php/mysql and rails up and running securely.

Major points to slicehost for the high quality walkthroughs- and for 20 bucks a month, it's more than worth it to just get a slice and jump in. That's something I'd highly recommend (No, i don't work for them, I'm just very happy!)