I bought both versions of Burnout Revenge (first on Xbox, then when I got my 360 that version) and the difference was huge for a port. The HD resolution alone made it so much better looking, while keeping it at 60FPS at the same time.
Now Project Gotham Racing 3 (a launch title) totally killed every other racing game at that time on a technical level.
Digital Foundry has just confirmed the resolution is the same as on the 360 which is to say 880x720. Looks similar to 360 (except gamma) but framerate worse than PS3 version so it goes 360>PS3>Wii U based on performance but 360>Wii U>PS3 based on graphics.