You didn't give much info as to what you were planning to use it for; those antennas are intended for "UHF CB" at 477MHz which is not a US service so I'm guessing that is what your planning to use it for and are therefor not based in the US.
That having been said, the main difference, aside from the physical appearance, is that one is "ground independent" while the other is "ground dependent". By that I infer that the "ground independent" model is a half wave design which does not need a ground plane (like a metal car body) so can be used on non-metallic surfaces like fiberglass boats, etc. or where there is insufficient metallic ground plane available. For 477MHz, you don't need much so if you are planning to use it on a car with a decent metallic roof or trunk then the "ground dependent" model should be fine; otherwise, if no metal available use the "ground independent" model.
-Mike