yeah they are quite noisy, i have added an intercooler to my son's (have read they are crap but not had a problem yet) to help keep it cool which makes it even louder.
the biggest problem is the ROD (ring of death) or 3 red lights caused by over heating but MS have now upped the warranty to 3 years. but i think the 3 year warranty only covers the ROD and nothing else, think everything else is covered by the normal 1 year warranty.