The first thing I noticed about the game play was how smooth the graphics and game play was. I actually got a hit in my first inning of play, unlike MVP which took me 5 innings of play before I got a single (I know no more about MVP). The controls for MLB are great for batting, especially the Guess Pitch feature. This lets you guess the type of pitch and if you're right you get an icon telling you where the pitch was fall. You'll also get extra power for your swing.
The game modes in the game are also pretty good. The Career Mode is interesting, since you get to create a player and follow him through out his career. But, the thing is that if you play this mode, you can't be the Manager or GM. You can't even make lineup changes; I guess they were just trying to play up the fact that you're a player and nothing else. But, I find it sort of annoying that I can't even make a trade or warm-up a relief pitcher.
The main thing about this game is the game play and for a portable game that counts for a lot.