Why ignore differences in appearance? I think that's probably the main thing other than possibly weight if you are a weight weenie. Along with the possibility they don't offer some gear combos or ranges in all of them.
Likely they'll all wear about the same. If there are weight differences, then that'll be difference in material used. Lighter usually being the higher tier product. .
More rust resistant? Less wear on chain?
All of that is going to depend on factors unique to you.