My brother bought a new elite xbox about half a year ago (after his first one broke several times and then its warranty ran out) and he's already sent it back once, so I don't think the problem is fixed.
Best to check out the games you want and see if the majority of them are on the PS3, which as far as I know aren't nearly as prone to breakage, and the price is comparable now. Otherwise you're pretty much guaranteed to have to send it back for repair at some point.
Unless you are particularly set on the new gen consoles, go and buy some ps2 games off ebay you've never played, I guarantee there's a bunch of great games you've never even heard of.