RE: Vtec or Ultratec ?
The "equipment" you're shooting, the XTec, is basically the same bow as the VTec. Same limbs, cams, and geometry; just a very slight 'bump/V' in the riser design.
If you're looking to replace the exact same "sweet shooter" that you already have, go with the Vtec. If you're looking for something just a little different, go with the UltraTec. Both are fine bows with 'state of the art' design.
If speed is your issue, shoot them both side by side with the same criteria. This is what we always try to do with our customers to assure them that they make the 'right' decision for their needs.
Good luck.