I got this earlier today without a second Motion Plus, thanks to GameStop being the only major retailer I've seen that isn't charging $20 for it. I'll probably hold off on getting a spare until I have a friend over to save me some time now.
I really like sword fighting, archery, basketball (you just suck at it, io, because I rain threes on the computer team), table tennis, bowling, and the air sports games. Swordfighting is probably the best use of the added sensitivity and the mode centered around beating up fools that come after you is fun for single-player action. Basketball is nice and simple, though I have no inside scoring game yet, just a good range shots and great shot blocking (with my face, too). Table Tennis capitalizes on the potential that the Wii Play version of the game had, but fleshes it out into an actual sport. Bowling is as fun as it was in the original Wii Sports, but with a bit more control that keeps those easy strike moves out of it for a while. The flyover mode for the plane games is a nice relaxing game that lets me fly around the island and explore without much pressure.
The games that I hate are canoeing (it's unresponsive for me), cycling (think of the most tiring minigames in the first Raving Rabbids game and you have an idea of what to expect), and somewhat frisbee, though that's more about me sucking at it and wishing I could pick/design a dog to be my partner. I still haven't tried Golf, Wakeboarding, or Power Cruising, so I don't have anything to say about those sports yet.
I really like the stamps system, which is Nintendo's attempts at achievments. There are five per game/mode and it adds more things to do outside of what the games already offer. I'm not a fan of the spam messages you get to your message board, as you get one per stamp, so don't think that you've gotten popular when you see that you've gotten a bunch of messages. I'd have really liked to see a stamp book that collects all of them in one spot and then fill up as you collect them in each game so that you could have a one-stop place to see what you still have left to earn.
I still wish that the game let me pick my team in basketball and any other applicable games since I'd love to have some choice to who I'm playing with. At least these games seem to be less team-oriented and more about pitting you against a friend one-on-one.