The 3DS is fully retro compatible with DS games so it won't be a problem.
I have bought Soul Silver and it was good to replay that great game but I think that W&B are better. They feel more fresh have more features. I enjoy this game as much as I have enjoyed Silver back when I played it on gameboy.
Rath, that's the thing, no more resting on laurel, you have to build a whole new team from the ground and it's exciting.