my wife has been doing LGA-CMH weekly since June. And since she would not stick to a single airline, she had only silver status on delta, and I had nominated her to Premier Associate on United. Well in October I finally convinced her that connecting on United rather than a direct flight would be in her best interest, (she has always wanted high status, just would never dedicate.) So with DEQS she just made 1k this morning, and is a happy little bee. And to boot while it takes theoretically twice as long to travel due to the connection, she actually says she finds it more relaxing since she has a chance to acclimate to the change while waiting in IAD.
Supprisingly the total travel time really isn't much longer, for some reason the direct flights were delayed 1-2 hours about 70% of the time, while with her connection she has only been delayed a max of 30 minutes maybe twice in the last 13 weeks, and been early about 40% of the time. So in all I would say the connection while adding extra flying miles and extra time sitting in IAD, has on average only added maybe an hour to her total travel time, but she has also been relieved of the aggravation caused by delayed flights (she is a nervous nelly type of person.)
Best part is she really doesn't get any upgrade possibilities since she is on the small planes, so guess who gets to use her CR-1's next year!! (I take the PS flights about 10-12x a year)