There's definitely a difference in service levels, and although I may bite my tongue after saying this, but if UA's going to cut costs somewhere, this isn't *that* bad of a place to do it.

I recently flew on the ORD-Punta Cana flight. It's approximately 2,000 miles/5 hours on A320...and the meal was a chef's salad in F. That was it. The flight departed around 4:00pm from PUJ, which is close to the dinner-time mark for UA. Even worse, there's probably little catering at PUJ, but the food that is eaten on return is loaded in ORD. So it sits for quite some time before being consumed.

Conversely, the following week I flew ORD-MEX on A320 which is ~1,600 miles/3.5 hours...and we had printed menus, champagne, a few different wine selections, etc. Additionally, the 5pm ORD-LAX flight has 3 menu options with ice cream sundaes.