The ease of use for both patient treatment planning and surgical execution once it comes time to perform surgery. It has not been easy finding any fault in their product. I would suggest trying out Tx Studio first because if your experience with Orthognathic Surgery is similar to mine (simple, short procedures), then there will be no reason why you should find anything wrong with them. My only suggestion is to make sure you have enough patients who are suitable candidates for such complicated surgeries. This program makes my life so much easier by allowing me as a surgeon to prepare everything beforehand and allow my assistant less work during the day of operation while also making things more organized when I'm at home after discharge from hospital.