Purchased it yesterday, it is vastly different mostly due to the way you control the skater. It is set out like the total punch control scheme used for the Fight Night series. One stick controls your movements, the other is for the execution of the tricks (up down for an ollie, down up for a nollie, half circle in is something else etc). It is something i am not entirely used to and not very coordinated in (trying to balance the skater, then execute the trick, whilst holding shoulder buttons to grab on to the board is difficult for my hands to accomplish due to the 360 controller).
Graphics are alright, although sometimes the camera angle can make things harder where you can't pinpoint the distance which you need to make to either jump over, or grind on an object.
I can't give a definitive view on the game vs Tony Hawk series, as i've only played a few of the THPS games (2 & 4 specifically). But i do think the landscape changes, due to the way you have to control your skater in this one vs the way you move around in the THPS series.