CAMBam is great for the price, I would give it all 5 stars, but since it is still in beta, I have to hold back the last one.  Don't let the beta status scare you though, it works great 99% of the time, I have used it without problems for 2D projects and it is simple enough to learn with some effort.  3D is more challenging in my novice opinion.  For 3D it can take a good deal of massaging to get it to get it to do what you want as I am learning currently.  I have confidence however that any bugs still needing to be worked out will be.

There is a great user community at their site, and the developer is active there as well.  Considering the cost of the alternatives and the amount of polish already on the program it should be at the top of the list of CAM programs - which is probably why it is the only one they sell here.