If I don't upload or download anything for three days I get booted regardless of my ratio?
Yes. The reasoning being:
1. leave your PC on for uploads if you're on vacation
2. if you can't, you can sign up again.
They used to have an option where you could sort of block you account temporarily, but they removed that (or so I've heard).
Azureus is a cool client, among other things, coz it's easily customizable. For example, you NEVER wanna use the default port since most ISP's squeeze those (those guys aren't as stupid as we tend to think). And because it has a frog for a logo.