The amazing new controls make this Mario sports classic worth revisiting. Wii Sports Tennis--your time is up.
Players of the GC original, however, might feel a little short-changed. Content wise, Power Tennis is almost exactly the same--save for a couple new courts and characters. However, I played the original quite a bit and I feel as if I'm playing the game for the first time. Front hand, back hand, lobs and spikes are all handled quite naturally--it'll only take you a couple games to fully grasp the controls. Don't think this game is shallow, though--unlike most Mario Sports games, Mario Power Tennis is actually a great representation of the sport. Sure, anyone can jump in and play, but it takes some real skill to master. You can even put spin on the ball, which is a nice touch.
The "Power" subtitle comes from the awsomely-over-the-top power shots in the game. If you charge up your shots (which is handled by positioning yourself directly in the ball's path) or get a good volley going, your power-meter will fill up and you can use either A) a power hit, or B) a power save. Power hits are exactly what they sound like, and power saves are used when you can't get to the ball in time. Use it, and you'll hit the ball from anywhere on the court. Deciding when to use your power hits and saves in yet another skill area in the game. Just make sure you set your conrol settings to "technical" so you can control your power shots manually.
Tournament mode is the single player attraction, but that can get old after awhile. The multiplayer, however, is simply unmatched. It's fast paced, fun, and intense. Get a group of skilled players together and you'll have the time of your life. There are even "item battles" for a more Mario-Kart-esque match. The lack of online is upsetting, but if you have some friends, the local multiplayer alone makes this worth a purchase.
My only complaint with the game (other than the lack of new content, of course) is the appropriately named "Gimmick Courses" which provide the random frustration that most mario sports games tend to have. I tend to avoid these as they take away a lot of the skill.
If you've never played Mario Power Tennis, this is a must buy. Not only is it addicting and fun, but it's cheap. It's also the best Tennis offering on the console (that is until EA Grand Slam Tennis comes out). If you've played the GC original, this is still worth a play, but you might want to wait for a price drop first.