I have the 18" Jet and I love it. It uses holders for the blades. You put the bottom end of the blade in the holder and use a hole on the side of the saw as a wrench to get it tight. Then you slip the holder into the lower arm and flip a lever to clamp the top end. The adjustment at the back of the saw is NOT the tension, it's just to get the arm parallel. You turn the lever to get the tension set. Once you have it set you're done - flip the lever closed and it's tight. DO use a bit of tape or something to mark the setting of the back knob though - it can wander when you don't have a blade in.
Add a foot pedal for good control whichever saw you get. I have the one from Harbor Freight because there's one six blocks from my house. Cost about $15. If you've ever used a sewing machine it's very similar.
The Jet IS about twice as much as the standard Dewalt but I'm very happy with my choice.
