First, the most advertised feature: the light. The light works great. The best thing I can compare it to is my Palm PDA. But if you don't have one of those either that doesn't do you much good. The light looks like it has a slight blue tint to it. I guess there's the potential to make the colors less brilliant, but if the alternative is not seeing them well anyway on the regular GBA, you aren't losing anything. I personally haven't noticed anything that bothers me, and I've tried out a few different games, but if you're concerned about that you should probably check out a demo before buying. All that really matters is that you can finally play in the dark with no glare. All of you who bought that first Castlevania game, or the Black Label Lord of the Rings game, dig them out of your videogame drawer because you can finally see what's going on.
The next big step up in my opinion is the battery. It's got a built-in rechargeable battery. The life (according to Nintendo, I'm not leaving it on that long to check) is 10 hours with the light on, 18 hours without. Mine came charged even though the instructions say you must charge it yourself. They say it takes 3 hours for a full recharge, but if you just can't put it down you can play while you're recharging, though it takes longer that way. If you play a lot of Gameboy, this is definately going to be good on your wallet. I have to wonder if manufacturers of AA batteries are concerned about this. All those kids playing all those hours of Pokemon have to add up to a lot of batteries.
I should mention that if you like to play with headphones, you'll need an adapter provided by Nintendo. And since it plugs into the same accessories slot, you probably won't be able to use the headphones and the AC adapter at the same time. I don't know that for sure though since I don't have the adapter, but the illustration in the manual doesn't show any sort of piggyback feature.
One concern I had was that the cartridge inserts at the bottom, rather than the top like all previous Gameboys. It looked to me like it might be awkward playing original Gameboy games since they would stick out. Well, the way your hands are situated, it doesn't get in the way at all.
If you own a GBA, you have to decide for yourself if the extras are enough to fork out another hundred bucks. It was for me and as I said, I'm very happy with it. I've tried to cover everything someone might want to know but if you've got a question I didn't answer here, post it and I'll answer it the best I can.
