The electric motor for both is same. The pumps are NOT. The pro series pump is a quiter, more durable pump. Hence PP backing it with a better warranty. The sportsman II has lesser quality pump that is made by a different company that the pump used in the pro, signature, and blade series. The pumps in the sportman's are significatnly lounder than than the pumps in the pro's and this seems to be the biggest issue people have with them. You won't find this info posted on any web site, but talk to some of the dealers and they will tell you. Now with that said, the performance seems to be good on both and there aren't many complaints on either models as far as their ability to grab and hold.