So I'm planning to do a fairly large amount of cutting (bigger stuff, not just blowholes and fan grills) in the near future. I have a Dremel but I'd like to invest in a jigsaw for the projects. I'm a ...

I'll assume you are putting a metal blade on that jigsaw if you're going to use it. But I'd say Dremel is better, it's going to give you a finer cut that is pretty nescasary when case moding.

Dremel has launched a compact yet powerful 3 in 1 Spiral Saw - a multi-functional system that can cut, sand and rout. Perfect for making quick and controlled cuts in wood, plastic, drywall, sheet ...