Really? I've found the opposite. I should clarify I'm talking about downloading a game, not installing it from disc. It's been a while, but as best I can recall, downloading games took like 5 or 6 hours. I found it really weird, because MS is so big on internet services, yet the downloads are like sucking pine tar through a straw.
For a long time PSN downloads were pretty slow but the past year (I guess) they've gotten much faster. When I say really slow I don't mean like dial up lol but yeah they were quite a bit slower than they should have been. I don't know what's changed but I find my downloads on PSN to be comparative or sometimes even faster than XBL.