
I think all you need is the brighter sp for all your GB, GBC,and GBA games And the new DSi for just DS games. For me either way I have to have two because I still want to play GB and GBC games backlit so taking off the GBA isn't that big a deal to me.
I like the bigger screen. My eye sight doesn't seem to get better with age. Good thing I haven't bought a DSi yet.