I believe the question that Marty first asked was if Reverse Draw Crossbows are the wave of the future, so while the answers provided above seem to answer that question, at least in part, I'm seeing a question that appears to ask "what's so hot about reverse draw technology"? If not, I'm misinterpreting the question.
Marty, while I agree with the answers provided by UL and SouthShore Rat I thought I'd add a little statistical data to provide some insights into reverse draw technology.
By it's very nature and the laws of physics, one of the things that make reverse draw so appealing is the fact that at its core, reverse draw is 47% more efficient than conventional draw. This means more speed at an equal draw weight to conventional limb technology.
Reverse Draw also dramatically shifts the balance point of the crossbow and brings the majority of the units physical weight closer to the shooters body as opposed to extended out in front of you. This makes holding steady when shooting free hand much easier.
Reverse Draw Crossbows are generally much shorter even with longer Power Strokes than conventional draw crossbows, so therefore they are much easier to maneuver in small or tight spaces.
Negative aspects - Price All this technology and R&D has a cost factor, so as already stated they tend to be on the pricer end of the crossbow spectrum. If you talk to anybody who owns a ScorpyD they would never shoot anything else. This is based upon the pure accuracy and speed they deliver.
As Jerry pointed out, there's a price point the masses are willing to spend for a crossbow. Performance and accuracy most of the time come second to the cost factors. For those who are willing to afford the higher priced Reverse Draw Crossbow they are rewarded with speeds and accuracy not attainable by the conventional crossbow owners.
Reverse Draw Technology is patented by the owner of ScorpyD, so therefore anybody else producing an Xbow utilizing the technology has some type of an agreement with ScorpyD. They have also patented several other major crossbow improvements such as their latest trigger / safety system, entirely new much more efficient cams, new spring loaded mechanical string stops and a few others I won't name here. This is what you are paying for and receiving when spending the extra dollars for their products.
My suggestion is to visit their forum and do so reading to gain a better understanding about RDT.
It's definitely not the wave of the future, but neither is a Ferrari when it comes to cars!
Xbow755