Ok..
I have jet and later I bought general 30".. Jet was a bit slow.. but the main thing is Jet started to fall apart on me.. During long session (8 hrs session).. the bolt which attaches the arm to the motor started to come off.. so after every half an hour or so I had to re-tighten it... The bell for the air disintegrated and it started to rattle big time... Definitely not for commercial use....
Replacement was general 30" (was on special so i got it for the same price as 16" so why not... )
huge improvement... so much quieter, more torque.. Blade replacement is easier and best of all.. the upper arm actually lifts so you can pass blade through drill hole so much easier and faster...
+1 for general scrollsaw... It survived several 8-10 hours long sessions in a row (big weekend job) no even a rattle...

Alen