I'm pretty disappointed but it's my own fault.
I didn't really care about the game in the beginning because when it comes to a game / genre like this, I'm only interested in the offline multiplayer aspect, and I didn't expect Mario Golf to have any being on 3DS and all. (Don't know why they've never released a Mario Golf on Wii or Wii U which would have been a great fit, but whatever.)
Then I read somewhere that it featured "local multiplayer", forgetting that's just what the Wi-Fi multiplayer is called, and bought it. Remembered what it actually was, whatever, that's fine, it's still local, just get another 3DS... and then it doesn't even offer download play? Meh.
Other than that (and that you can't save while on a course for some stupid reason) the game seems pretty well done after playing it for an hour or two, it's just not my thing.