Thing about kites like the 2.3, they're smaller... This brings a faster style into play, faster reflexes and that feeling you get from speed.
It's fun, and has it's own flavor... A full size kite like the 2.5 is a bit slower, the steps from move to move are a bit clearer, and it can be more elegant in most cases.
Cost aside, the choice also comes down to what you're looking for.
2 cents in hand.