I have a 360. I've only had one issue with it (less then I had with my first PSP) and had to get it replaced. I've got one with the "new" heatsink in it and it's been going along just fine. My problem was actually the DVD drive, not overheating. It got knocked around during a move and busted.
I've thought about getting a PS3, but there just aren't any games I really care about. I've not cared for Metal Gear Solid for some time. I liked the first one for the story, and I feel the others just don't measure up. It isn't a game that I've gone to for gameplay. Little Big Planet seems like a lot of fun, but that's about it. Anything else I can get on my 360, have better online, and have better exclusives. I've also noted a few games going 360 that may have gotten me to pick up a PS3 (such as FFXIII). At this moment, the only real appeal to me of the PS3 is the upscaling of PSOne and PS2 games on my HDTV, and unless I find an older model, I'm out of luck on the PS2 games. The blu-ray would be nice, but I'm not that worried about it. I don't watch movies enough for it to make much impact, and the few things I will watch regularly aren't on blu-ray yet and likely never will be. I don't think they animated Batman or any of the other Bruce Timm stuff with HD in mind.
Basically it comes down to games for me, and the 360 offers me anything I might want on the PS3 and more. Shoddy hardware aside, I get far more use out of it then any other system I own. My friends own 360s, so it's easy for me to play online with them and that's a big boon right there. If you are a big buyer like some people I know, the 360 Marketplace is far more extensive then the Playstation Store.
I notice that many of the people on the boards that claim to play their PS3 more don't generally have many PS3 games that you couldn't get on the 360. The only thing that is preventing them from playing their 360 more is their unwillingness to pick up the 360 version of a game over the PS3 version. Now if they were playing the PS3 more due to exclusives, that might mean something, but to me, playing a system more when you are playing games avaliable to either system doesn't mean much. Especially when they are buying the PS3 version over the 360 version and it has been shown to be the weaker version (such as with Fallout 3, which is noticably better on 360).