OK, I didn't look hard enough, sorry. The alternative one on the right has a greater angle it can sweep through. The one on the left is the RAM original, but the bolts and wingnut pointing upwards made it look slightly odd.
The alternative one has less surface area touching the ball, and is more likely to bend/flex (less strengthening material in the direction that the screw tightens - left to right in the pic), so will it grip as well as the RAM original?
But I guess the amount of weight (a GPS unit, Rae?) won't create much of a force.