I like Mr Dremel a lot too ... for thinner F/G I've used the spiral cutting bits in the Dremel. I also like my 4.5" angle grinder with a cut-off wheel ...
For really finished cuts try rough cutting with a sabre saw or cut-off wheel leaving 1/8 inch or so of material then use a router with a counter trim bit to finish the cut.
To get cuts really straight, clamp a straight edge tothe work and use the router. Likewise with round holes ... make a plywood template and stick it to the work with double faced tape then use a roller guide bit in the router.
For small spaces where the big router won't fit, I have a small trim router ... a cheap model from Harbor Freight ... works fine. Just don't try to take too much material in one pass.