After being PM on DL for the past 6 years I switched to UA this year primarily because of its IAD hub. I have not been disappointed. UA offered me gold premier executive instantly (comparable with DLs gold medallion). UA has a economy plus section for its frequent flyers that gives you more legroom. Also I have been upgraded on 70 percent of my flights this year even though I purchased deeply discounted tickets (even HKG/ORD, LHR/IAD). I have found UA employees to be much more pleasant than DL, especially the FAs. My tally so far this year is DL -- 0 miles; UA 65,000. Travel plans for the remainder of the year will give me top UA status. My only regret is that I stayed with DL far too long. Finally, it's nice to travel somewhere without connecting at ATL or CVG.