My one year, one month old powerbook is gorgeous. Only flaws that came up were me using it in an unairconditioned environment last summer so i have the sweat stains, and a couple of dents from when someone dropped my bag. Neither of those really apple's fault (though it is the aluminum's) and it still runs great.
My sister's 5 month old powerbook is equally great, though without any dents or stains, and a higher rez screen (it seems so wrong she has a nicer model than me)
My friend just got a macbook after being hardcore windows, he seems to really like it.
And my other got an imac and he only has problems with windows crashing, none with OSX or the imac (though he said burning discs get really hot..which i'd say is expected)
Oh, and another has about a 2 year old 12 inch powerbook, run like a charm despite being beat to hell. It's impressive actually.
So pretty much..5 switchers, no bad stories.