I just tried Ubuntu on my MB Pro 5,5 yesterday. It wouldn't come out of resume (after a minute or so of screwing around, it would lock up to the point where I could see my desktop background and a useable mouse cursor, but nothing else happened). I haven't had time to search for a potential solution to that issue.
I was Linux trying because I've been having major slowness issues since Mavericks when displaying pictures. There are lots of proposed solutions in the Apple forums, but none seem to work for me; it's still slow. I know it's a 5 year old computer, but I wasn't having an issue under Mountain Lion! The delay started when I upgraded to Mavericks. And, frankly, a Core 2 Duo processor ought to be able to render a picture within a few seconds; it can take 20-30 seconds in Preview or LilyView (an app I downloaded when this problem first appeared). I checked; it's definitely processor bound; I was hoping perhaps a flash drive upgrade would help, but it's the processor that spikes, not I/O. From what I read, the issue is that Mavericks went fully 64 bit and the old 64 bit processors really suffered from the change... maybe trying to encourage me to buy a new one? You know, I still have a Mountain Lion disc around...
I was testing Linux on it because I was hoping it'd be faster, but unfortunately Linux wasn't working all that well on my MBP, and RAW files and Linux are still a bit of a beast. I could probably work around the latter, but the former was kind of a PITA.
I hate to buy a new one because they're damn expensive, and my old one should be working fine. Rendering 16 megapixel pictures is not one of the things that's driving processor design these days.