I'm gonna copy-paste some impressions I first posted on IGN, since no one there is reading them. I'm a lazy attention whore. ;)
Let's Catch is pretty interesting and original, perhaps not in terms of gameplay, but certainly in concept.
I got interested in trying it after listening to an old Destructoid Retroforce Go! podcast: the girl describing it totally sold me on it. She likened the story mode to Phoenix Wright, in that beneath the cute, casual wrapping are some serious stories and issues. Let's just say she had me at "Phoenix Wright", though perhaps I wouldn't make the same comparison.
Anyway, the gameplay itself is nothing too special: you flick the wiimote to throw a ball, you press A and B at the same time to catch it. Flicking the wiimote with just the right amount of force nets you more points, whereas when catching, your timing determines how well you're doing and how many points you'll get.
What makes the game interesting, however, is the story mode. In it, you throw and catch a ball with your neighbours and get to know them. Play well and they'll keep opening up to you about the issues they're facing. Do poorly and they'll stop playing with you. The more you listen to them, the higher your "friendship level" gets, and eventually you unlock new characters to play with.
And so you throw a ball while listening to a widower dad who thinks his daughter is emotionally shutting down, or a woman who's thinking of cheating on her boyfriend with a married coworker (!).
I don't want to say too much because really, the enjoyment you get in this game is in the discovery, in listening to these characters confide in you and in piecing together the puzzle.
The Story mode is about 3 hours long, and I'd say it's the main draw of the game. Beyond the Story mode there's a bunch of score attack modes that could appeal to fans of arcade action, except I'm not sure if the game gives enough feedback when you're doing it wrong. It might frustrate some players to feel like they're throwing consistently the same way, yet not always getting consistent results. You can see on screen if you've thrown the ball too hard or too softly by looking at the character animation, but it's hard to get a feel for it when you're actually doing the motion.
If you're new to Wiiware or are into more traditional games, there are quite a few games I'd recommend before this one. But if you can easily spare $10 and are looking for a pretty original game, I say go for it.