I don't know, do they advertise "virus checked downloads"? >:D
I think all the popular websites are reasonably trustworthy otherwise they would not be popular with the clientelle they attract. However I am one who puts nothing to chance and Imake sure that AV software is updated everyday and I scan EVERYTHING before running it. Even commercial stuff like Office and even mIRC. This isn't to knock the things I use, it is just called being careful.