I'm very happy with my 18" Jet. They use a lower blade holder and give you three so you can change blades in a snap if you want.
I generally use the same holder for a particular type of blade so my blade changes aren't that fast. Then again, I'm not in a hurry.
You pop the lower holder into place, set the top of the blade into the clamp and then flip a lever to bring it up to tension. It's always the same tension. Setting the tension is slightly different on a Jet. The big knob at the back is just to get the arms parallel. That affects tension but it's very crude. Take the advice I got from someone else and mark your knob (I use some tape) in case it gets moved.
You set the tension by rotating the flip lever that tensions the blade. Twist it right for tight. left for loose.
If you're doing a lot of fret work you'll like that there's a slot right to about 1/8" from the front of the saw table. Pop the lower blade holder out and you can go up through a hole right up front. Then you can slide back to the right spot, pop the holder into place and tension the blade.
