I haven't had experience with edgecam, but I have worked with Mastercam when it was more DOS based (Version 8,9) and with the new versions up to X4. I didn't think the new software was that "buggy", but it depends on the system and the work you are doing. For the basic 3 axis machining you are talking about it may be a little overkill, but it would leave a lot of potential for you. I used it for everything from designing fixturing to complex 3D surfaces. It also depends on if and what you use for modeling software. If you do any 3D modeling, like SolidWorks, you may want to see which ones work best together.
Basically, I think Mastercam is worth it and the way to go.