Mirror's Edge is not worth the buy, but it brings much more to the table than an occasional rent.
There is no other game like this, it is simple as that. Mirror's Edge is, to my knowledge, the very first true "free running" game. There is no stopping where one can go and what one can do. Yes, there are games similar to this but are third person games. Mirror's Edge is a first person game that actually makes you feel you are the character (Faith is her name). It is short, but this game will have you coming back for more until you defeat the story mode. A must play for both PS3 and 360 owners.
Graphics
Fantastic PS3 graphics. Jumping from rooftop to rooftop looks amazing and further adds to the incredibly realistic feel.
Sound
Faith has a lot of noises that come with her: getting injured, jumping, and all of the great sounds that come with landing, rolling, and climbing. Great music as well.
Value
This game will not keep you coming back very long. There are time trials but they do not do the justice. The new downloaded material helps gamers come back but i haven't been able to play it. Mirror's Edge would greatly benefit from a free running mode where the player could endlessly run around and explore.