I was looking at an pro impact from opro and a $105 version from biteme. The biteme was slightly stiffer and had more coverage behind the front teeth. I didn't wear it since it was a partners and would have felt slightly awkward in my mouth. Both were very thick. I don't think you can go wrong but the coverage just seemed better. Couple all of that with the fact that biteme is pro mma (whereas opro is not sponsoring anybody in mma) and puts a lot of emphasis on the mma market and I woould go with them. Plus if you want to spend the exta$ you can get some very cool designs.