I shot both of them last week.

The supertec is real fast and without a stabilizer you notice a little vibration in your hand. We screwed in a doinker and poff vibration was gone. It shoots real nice. The draw force isnt very harsh especially for the speed it puts out.
What I didn't like about it is there is no valley to speak of. If you let it creep at all it wants to tear your arm out of the socket so watch out! If you shoot with good form and back tesion this would be a great bow for you.

I will let some of the Bowtech gurus tell you about the extreme. I may be in the market for this bow as well. good luck.