The old xbox dashboard was terrible, hard to navigate too many categories too much information on show in one place and just all around messy. I do agree that they have pretty much ripped off the PS3 dashboard, which means they're finally doing something right atleast, I love that interface.
It was piss easy for me to navigate, I didn't even have to look at it.
It went like this > Xbox on > press UP > press "A" > Game Loads, easy as pie.
And if I wanted my friends it was 2 clicks down / Last.fm was 3 with on to the right and the Games Marketplace was somewhere, probably 4 down but I rarely go there since I need a new HDD before restarting my mini archive

PS3s design is a pain for me to use, was in a friends house and he told me to load a game up while he went to the shop...after 5mins he came back to me sitting on the laptop because I could not figure out how to get the game one. (His don't load automatically when the disc tray closes.)