I have watched J Lo perform a few times, and she will invariably turn her back to the camera, spread her legs, and bend over to the floor, accentuating her behind. There is no attempt at any artistic flourishes or teasing; she is in fact mooning her audience/nation/world.
Also, she evidently can’t dance. While Shakira was in fact dancing, J Lo was tumbling and being twirled and tossed around by the men lined up doing whatever they were doing, or she was spinning around on a pole. I think she made a movie doing that.
I agree -- Shakira also looks like she is kind of having fun up there as opposed to just trying to be as sleazy as possible. JLo seems to aim more for the pure sexy/sultry look, and I wasn't a fan of that either.