The question is how much you trust Scott Kirby to deliver on his promises of United Next, and not to run the place into the ground. The last two weeks don't look promising. It's still a poorly run company.

Plus, you said yourself you'll have to commute at United until you can hold DEN (which I understand is a fairly senior base there). You didn't say where you're commuting to at DAL, but there's a big difference between commuting from DEN to NYC or ATL and commuting to SLC or SEA. Or move closer to a base. You'll probably make more over your career and have more stability at Delta.

None of us can tell you what to do, but I'd say starting over now at what may be the end of the hiring boom may not be a wise idea. You surely have 1000 or more people behind you at Delta by now if you're flying the line.