Oh man, I doubt have any experience with these AIO models, but I've heard they can be a pain. Much more proprietary than a desktop system.

I say take it super slow. Do lots of research. Ebay saved searches are your friend.

And don't forget to sit down and use it. I have a bad habit of not actually using all the computers I fix up. Using them tells you what needs to be upgraded. Otherwise you're just throwing parts at it for the numbers.