I'll be splitting some flights between US and UA over the next couple of months. DL is my primary carrier, but will have a few high-mileage flights. As far as flying, it's a mix of the 2, depending on the destination. I have no status on either, and should make 1st tier but doubtful on 2nd tier elite. My question is, when banking miles, should I bank into UA or US? Which one has better reciprocal benefits via Star Alliance when traveling on the other? Are they exactly the same when it comes to that aspect (aside from the merits of each program v. the other)? Does it even matter if I'm not at least Star Gold one way or the other?