It really simply comes down to suit color preference, since they’re essentially the same figure. That’s really it.
BvS has the glue residue issue on the suit above the S, but some are worse than others. Some I’ve seen caked in it. Mine luckily has been okay, and only has a slight tint of gold when put underneath a bright light. Under normal lighting it looks fine. I really liked BvS UE, so I’m sticking with my BvS figure. I also like that he can represent the Knightmare angle should you decide to collect some Knightmare figures.
Since ZSJL was released, the JL one now is basically just a brighter suit version of BvS. It has the additional heat vision sculpt, which to me is sorta a gimmick since I never use light up features on my figures. Some of the S logos on the suit I’ve noticed have been inconsistent, with some for whatever reason being smaller and others being a larger (correct) size.