Check Valve in circulator. Remove or not.

I'm replacing the circulator pump (bg100) with a UPS15-58FC grundfos 1/25hp which comes with an easy removable integrated check valve. I've seen a few people suggest removing this altogether from the unit.. Any pros/cons to that. I'm guessing that might improve flow somewhat? I wouldn't want to do anything that would be economically inefficient or great harm the system. I've read up a little on the valve to find out what it might do but I don't know if its presence is all that necessary.