For what it's worth, I'm a woodworker by trade, so I guess I'll offer my two cents...
Take in all the advice given thus far - consider your space & power requirements, rip capacity, dust control etc.
The best blade is a Woodworker 2. It's $110 & worth every penny. It's thin kerf will aid an under-powered saw, & will leave a perfect cut line. When it's dull, pack it up & send it off to Dynamic Saw in Buffalo for sharpening - it's a bargain.
Install a zero clearance throat plate. It will greatly reduce tear-out along the bottom of the cut.
Have adequate infeed & outfeed support. This will help you move the material along the fence more easily & accurately.
Get the best fence available / that you can afford. Lower quality fences will flex under a heavier load ( like a large sheet of plywood ). Some smaller machines combat this with locking mechanisms at both the front & back rails.
No matter if you buy a brand new machine or a used one - spend as much time as needed setting it up. Make sure the fence is square to the blade. Check the accuracy of the fence ( & it's ability to make a repeatable cut ). Make sure the blade's dead-stop @ 90 degrees is right on.