I honestly have no idea what kind of performance increases you can expect. I think its mainly for optimizing fuel ratios once you have and exhaust, filter or any mods that increase the amount of air the motor is pulling in. But I heard many also say that it reduced vibrations and overall harshness of the motor, even in stock form. I haven't looked into the power commander so I cant say how similar they are. I also agree that the instructions seem a bit overwhelming at first, but it looks like HMF, Weiseco and some other reputable companies offer this same device with their name printed on it, so it must be a decent setup. I emailed the company and asked if they had any plans to release a rebel version and have not heard back in a few days.
2017 REBEL 300 ALL STOCK.