I've had a ProDrive for four seasons now. If you want or need reverse, there are only two tried and true brands: ProDrive or GatorTail.
With the newer models, I don't think gear vs belt is even an issue. If you want or need instantaneous reverse you want a GatorTail. If you want or need true full power in reverse, you want a ProDrive. However, the prodrive takes about 4 seconds to rotate the drive into reverse, so it isn't for precision maneuvering. They both have basically the same engines, so it is all about the drive.
The good folks at ProDrive stand behind their product. I'd buy another one tomorrow.
Things learned: Although the mud motor part of the system is bulletproof, remember that the power comes from an engine intended for installation on lawn mowers and stump grinders. It takes special care if used around salt water.
Do not modify the engine. Mikuni carbs, monster exhaust, etc., void the factory engine warranty and makes them temperamental in the cold. If you need more power get fuel injection (new this year) or hang two of them on the back of the boat.