The only real difference in a pro-trax front end, and a standard long travel front end, is the spindles and clevis' on the arms. Rather than running heims on the arms, they run the heims on the spindles turned 90 degrees so there is no lateral movement, and can extend itself longitudinally until the shock is fully extended.
They claim you can get 16" of travel out of their front end, but that is not likely on a banshee, as the a-arm pivot points on a banshee is so wide, you are limited on shock length. Take for example, a YFZ450R front end: Almost completely center mounted a-arms. I've seen long travel setups for these bikes run 20-22" shocks. You would have to have +6 or better a-arms on a banshee to run shocks that long. Long shocks doesn't ALWAYS equal longer travel. It's all where the lower mount is. You could run 11" shocks and have the lower mount as close to the a-arm pivot as possible, and pull 12-14" of travel. The bike would ride like complete and utter shit but it's possible.
It's pretty old technology that the race industry gave up years ago. ATV suspension is pretty far behind in terms of technology. I see stuff all the time being introduced as "the first of it's kind" in the ATV world, but has been used for EVER on sand cars, and race vehicles.
So yes, it's a great front end. Do I think the average person would benefit much from it? Probably not. If you're not skying the bike over 110ft gaps at 30ft in the air, get some nice longtravel arms, and some good shocks, use your stock spindles, and save some money in the process.