A Dremel is extremely handy, but it's important to understand the limitations. I view it like I view duck tape - it's often useful, but it is absolutely never the best tool for any particular job.

In this case, we're talking about cutting PCBs and wood in straight lines. A Dremel is not only "not the best," it's among the worst tools for that job. They're very difficult to cut straight lines with and they make very fine dust, which is not ideal with fiberglass boards.

If you're trying to avoid the expense of a real power tool, for these purposes it would be hard to beat a hardware-store hacksaw with a couple different blades and a miter box.