Just want to throw some more praise on this - I've played both of the existing Wii disc golf games (Tiger Woods + Wii Sports Resort), and this game is vastly superior when it comes to replicating real disc golf. As others have pointed out, the discs fly with little-to-no initial turn, and will generally hold their initial line for the whole flight, but they did a good job capturing the effect of nose angle - throw a nose up shot and it will flare and fade, throw with the nose properly down and you'll maximize distance and minimize low-speed fade.
There's definitely room for improvement in the physics model, primarily by adding initial precession based on amount of spin and different flight profiles for different types of drivers with understable to overstable flight behavior. Also, as mentioned by JesseB, you can't throw more than 320-340ft on flat ground, which while accurate for my personal power level isn't what you want in a video game; you should be able to throw 400-450 if you fill up the power meter during a shot.
A couple of things that are really neat - when you get hosed with a bad lie, you can try grenade shots/extreme anny backhands+forehands/rollers and they all act remarkably similar to real-world shots. The forehand roller is a legit escape shot in this game! Also, the interaction of the disc with the ground is really well done- discs skip when they should, cut when they should, etc. They also have pretty accurate sound effects for discs hitting objects/the ground.
Other thoughts - putting is a little too easy as compared to real life, I find that within 50-60 feet I'm about 85% in this game, and I'll hit 80-100 footers about a third of the time. This works nicely with the lack of distance on drives, however, because on the Gold(hardest) tee settings, you end up with a lot of 60-90 footers for birdie based on the hole lengths in that difficulty setting. The 18 holes in the game are really comprised of three different 6-hole courses in a park, mountain, and winter setting, and while there are three different tees and two different visual settings (day/night), it would be really nice to have more courses to play. It is really cool, however, that several of these 18 holes are real pro par fours in the 550-700 foot length range.
If you're somebody who's holed up during the winter due to weather or otherwise just can't make it out to the course very often, I highly recommend this game as a way to get your disc fix. The only downside is that it's not cheap - $100 for the Move Starter Bundle.
With the accuracy of these controllers, I really hope some developer creates a true disc golf game with multiple real-world courses, different discs, pro players, a progression system where you build skills/earn money for winning, etc. That would be amazing.