All of these gear reduction starters that are being sold by whomever are basically all the same. They start off with a tried and true Nippondenso core, and then just have adaptor plates machined to fit all of the various applications. There are a slew of different gears available, so something can be found to match any situation.
The big advantage to these starters are they have higher torque at a higher rpm, so they spin the engine much faster while using considerably less current. They also weigh less, and can be repaired (if that is ever necessary) by any local rebuilder. Now that I think about it, there are NO disadvantages. Well, there is that pesky concours judge.