I hadn't planned to take a physics class, but I got hooked after checking out the first few videos of this one. I love the way the instructor, Andy Brown, starts each unit off with a big question inspired by a historical discovery from around the world. It gives you a great sense of motivation as you learn how the great thinkers of the past made their breakthroughs, and how you too can solve seemingly impossible problems.
I already took physics long ago in high school, so for me, this course served to reignite my interest in the subject. You don't need to have taken physics before, but you must be quite comfortable with algebra and fairly comfortable with geometry. Although trigonometry is explained in the course, I suspect you'll find it tough going if you haven't previously been exposed to it.
Most of the time, the class seems intended for someone who has never taken physics at all, but sometimes it moves too quickly through various equations instead of reiterating the ideas behind them. They sometimes neglect to give you enough practice with each new technique, particularly later in the class. I found myself stymied by a number of homework problems in Week 5 & 6.
Another annoyance is the lack of notes or at least a list of equations. It takes too long to rewatch the videos looking for a certain equation, so I would end up searching on the web or going to the discussion forums. Luckily, if all else fails, you can always watch the solution videos if you get stuck and then give the questions another try. If you're new to physics you'll probably have to check the answers a few times, but that's okay.
I hope Udacity will consider making an expanded version of this course that covers some of the issues in more depth and gives students a bit more practice with each concept. I'm very glad for this quick intro, though!