The counterweight style is called 5a. You can do it with any yoyo for the most part. You just need to get a counterweight. Most drill a hole in a dice or whatever suits them. Though Duncan sells like a pack of three counterweights for fairly cheap.
I suggest using a plastic yoyo for starters, since it won't hurt your wallet, nor the yoyo as much if it hits the ground.
The YoyoFactory Plastic Grind Machine 2 (PGM) plays well, and has hub stacks; so you can grab the yoyo from the side and it will keep spinning.
It retails for about $30
The YoyoFactory Protostar plays very well, also. It retails for like $35 I think. The play style feels a lot like a metal yoyo.
Also, congrats to Jensen Kemmitt of YYF for becoming 1a world champion.