Pros: Great visuals, speed of play, and intensity.
Cons: Was a bit pricey for a PSP game.
The bottom line: This is a great game and so far is the only game (PSP) that made me put down Wipeout Pure, which is an all-time favorite.
I am new to the PSP and own three games currently. They are Burnout Legends, Wipeout Pure and Lumines. As some background, I normally am not a fan of arcade-style racing games as I would rather play PGR3 for example.

With that said....

I got Burnout Legends for the PSP last night and could not put it down. I played for about 4 hours and unlocked just under 20 cars (with plenty to go), and made it through about 5 events in the World Tour.

Gameplay:
The gameplay can be divided into several segments such as Race, Pursuit, Crash and Rampage (I think that is the name of it) and the World Tour encompasses all of these.

In Race, you do just that in that the goal is to win while avoiding crashes. Race is fun but to me is not the focus of this game.

Rampage (I may have this game mode misnamed) is the mode where you do your best to take out opponents. This is in my opinion, one of the best game modes. Here you get the slow-motion takedowns, the freeze-frame signature takedowns and the pure enjoyment of devouring opponent cars. The goal is to see just how many takedowns you can get. Can you get doubles, triples???

Pursuit is where you basically chase an opponent(s) down and bang the snot out of them until they crash. You are timed so kill'em quick.

Crash mode is where you try to create major traffic damage by crashing and then turning your car into a bomb. Once you blow it up, sit back and watch the carnage.

This is a basic overview of the game modes and I hope this helps.

Graphics:
I was very pleased with the speed as well as visuals relative to gameplay. The visuals are very fast and very good in my opinion. The PSP seems to handle the graphics very well. The slow-motion visuals when you perform a Takedown are enjoyable as well. They also give you a chance to blink if need be. The speed and intensity of the game is very well done in my opinion. When you are winning a race and have two laps to go, you will be stressed to not wreck on your own or get Taken Out!

Audio:
The game seems to have music ranging from very fast alternative to less aggressive music but still upbeat. I am a fan of alternative and punk music (background) and have enjoyed the soundtrack of this game. It is more lyrical than the soundtrack of Wipeout, which is upbeat but more techno or electronic. The music of Burnout Legends definitely gets you in the mood to drive fast and crash tons of cars!

Depth:
There are many games to play from Race to Pursuit to Crash and I think a few more. I think these were in the single race scenario. When you enter the World Tour, you get all the game types in different cities. There seems to be a ton of cars to unlock and race. I think there are over 100 from my recollection.

Replay Value:
If I happen to win all the golds, get all the cars, master all the events, I still think I would enjoy this game as it is a great game to pick up and play for 5 minutes or several hours.

Overall:
I tried the DS as I was of the opinion that any game I would play on the PSP, I would rather play on a full system. I was wrong. This game makes me want to play the PSP a lot, just ask my girlfriend. The visuals are great, the intensity is fun and there seems to be a lot of game left to be played. My only gripe is that this game seems to be priced well above the other titles I bought. I paid $50 for it and am ok with that since I love it. If you can find it for cheaper, all the better.