After a day spent researching, it seems to me that mileageplus and skymiles is effectively the same -in terms of qualifying, benefits, and general reward travel. Aside from ticket pricing (which is often close enough to not cause worry), what should I consider when deciding which airline (United or Delta) to spend my money with? They seem the same in general. I don't get it...

I'm traveling between NYC and Denver most often. I would likely be a gold status on each.

Any thoughts appreciated-