Tomb Raider Underworld, and PS3?

Okay so iv had PS1 PS2 a long time ago and would play alot of the TR games and LOVED them. Well I havent had on gaming system for years now and i wanna get one. I was thinking about gettin the PS3. I also heard the 360 is good too. which one should i get? I have a HDTV so im thinkin the PS3 would be a better option. what are ur thoughts? which is better? Also i am super excited for TR underworld to come out! So atleast either way i can paly it on either system. I heard mixed reviews about the last 2 TR, about being really short and not challenging. Does anyone know if this game will be more in depth and challenging??