Not all jig saws are created equal. Perhaps the most important feature to look for is a good blade guide (a little grooved wheel that backs up the blade). I have an old cheap Craftsman without a blade guide and a more expensive AEG German jig saw. The difference in performance is significant.

Some jig saws have quick-change blade clamps that use the Bosch style blades. Others us the old standard blade style that you clamp in with set screws. Many of the quick-change models will accept either style blade. Porter Cable also makes a jig saw that uses a bayonet style blade.

I would disagree with the person that claimed that jig saws are not good for cutting thin stock. That is what they are designed for. The roughness of cut can be minimized by the proper blade choice. Smaller toothed, narrow-set blades cut smoother, but slower. Blades that cut on the upstroke are available that keep the bottom side smooth. Blades that cut on the down stroke are availble that keep the top side smooth. There are blades designed to keep both sides smooth by having no hook on the teeth, but I don't have any experience using them.

While I think Japanese pull saws are fantastic tools, I tried to rip a coaming lip that is made of walnut and ash laminated with epoxy a couple of days ago with a Japanese Pull saw. I tried both the rip side of the blade and the crosscut side. It didn't really cut it. My jig saw made a very smooth cut. It pays to go slow on a cut like this to ensure a straight cut.

Most jig saws have a blower that keeps the sawdust away from the cut line. Some do not. This is an important feature, especially if you are using an upcut blade.

Some jig saws have a plastic base cover that prevents maring soft surfaces. This is also a good feature.

There are also cordless jig saws available. Makita has a nice one though it lacks a blower.