My thoughts.... Generally I am fine with DL for dom flts. However, getting UGs as a FO for the cities you mention is difficult regardless of the airline because these flts tend to be very elite-heavy.

For intl travel, I prefer *A. IMO there are more and better options and most anyone will say their award travel is easier and less expensive.

Since it sounds like you might be doing more intl travel, I would be inclined to look at UA but of course, the response could be very different next year.