So I picked this up, and two motion plusses. I've played two exhibition matches against my roommate, and I'll give some feedback about it, for anyone interested.
All information is with the use of the Wii Motionplus (M+), and there are none without said device. The game may play completely differently without it, but those impressions are not included in this quick review.
To begin, motion control, or at least, how the game interprets it, does not seem to be 1:1, unfortunately. Often, I'd swing with a clear backhand stroke, and have the character on screen use his forehand. Not several, but a few returns and volleys were ruined by this. However, the motion plus does read the type of stroke you're using, as it relates to topspin, slice, or a flat hit fairly well, better than other Wii Tennis games I've played.
The game has a few different movement options. You can allow the game to move your character for you, for instance, or plug in a nunchuk and run yourself. After a few quick tries on a ball-shooting machine, I determined that the auto-run feature just didn't make the cut. Often, the character would be confused as to whether or not a backhand or forehand shot would be adequate, and stand in the middle--essentially, without a players swing, the character winds up directly in the ball's path. To rectify this, my roommate and I decided we'd prefer to choose our shots, and moved to nunchuk controls, and we were happier immediately.
Beyond that, characters have difficulty changing directions and running forward and backwards. They can run left easily enough, and run right easily enough, but if you overshoot where you need to be, you probably won't be able to turn around very quickly. Often, it was enough to win a volley by repeating hitting the ball to the same corner of the court: The other player will try to return to the center of the court, and characters can't change directions quick enough once they see that you've returned the shot in said corner. An added issue with control, at least with two players on opposing sides of the court, is the camera. When the ball is hit to the corner, it would move off camera, except the camera shifts its angle to rectify this problem. Normally, this would be an intuitive solution, but, unfortunately, the change in camera angle also means that the direction you're running in (Precisely where you are pointing the joystick, relative to the direction the character is moving on screen,) changes. Since your characters cannot alter their directions quickly, this ended up losing several volleys for us. Additionally, characters do not run up or down the court with the same speed they run left and right, so it's very easy to anticipate and believe you'll make a shot, and wind up running short, not reaching the ball.
The last issue is one I'm not certain of, myself. There is a slight delay of swinging and the screen transitioning into swing. If you wait to swing until the ball reaches your on-screen character, you may wind up swinging a teeny bit too late, missing the ball. As such, it appears that the timing to hit the ball early, and in the direction of an early swing (toward the left from perspective of a right-handed forehand swing), is very wide, and the timing window for a directly forward shot and one that travels in the direction of a later swing (left from earlier perspective), is increasingly narrow. It's very possible this is an issue of my own, and not what I make it out to be, so take it with a grain of salt. I haven't had enough experience with the game to say one way or another.
Characters are caricatures of themselves, in several cases offering little resemblance to their real-life counterparts. They are lanky, with large heads, and despite the length, have a slower than expected stride. Default champions have a 3-5 star rank relative to their individual fame, and possibly related to ability. When you create your own character, this character has no stars, so it is assumed that victory and success in the single-player mode can raise the character up to the five-star level. The one character I made, when tested, didn't seem to have an speed or power issues, so I assume that the rank has more to do with relative fame than ability. Characters are larger than they would be in real life, so the court appears to be smaller than it is, but since movement speed doesn't match character size, the game retains the pace of a normal tennis match, and doesn't contain endless volleys.
If you were to compare the game with Mario Power Tennis, I'd say it is marginally better, despite issues with running and recovery speeds. Button presses are used for lobs and drop shots, but detection of forehand and backhand, as well as slice and topspin is done entirely by M+. Ball direction is conveyed by the timing of the swing only, it seems, though it could be influenced by the angle of the Wii-Remote, as well. Controls are, in no way, 1:1. The in-game character does attempt to hold his racket in a similar manner as the player, but does not nearly capture 1:1 motion. If the game believes you swing, the in-game character does a full swing, regardless of your true motions in reality, and sometimes, as mentioned before, it misinterprets forehand and backhand. The same flaws present in Mario Power Tennis's re-release, and even some from Wii Sports' Tennis are present, though detection is better than those games, in most cases.
All-in-all, despite the listed shortcomings, the game feels paced like a professional tennis match flows. Characters aren't as quick as in mascot-type tennis games, but rather a little more realistically, despite a caricature appearance that would leave other impressions at first glance. I point out the negatives more than the positives because I was expecting more. 1:1 was promised, but is not delivered in any way I found tangible. If you're a fan of Tennis, then you might like to pick this up, but the increased control is only marginal at best, and not worth an upgrade from Mario Power Tennis, or even Wii Sports' Tennis, if you're not. It does contain current-day and previous/legacy tennis champions, but they're relatively unrecognizable compared to their real-life counterparts.
Hopefully that helps things for those on the fence.