The good
I agree with a lot of the negative comments but I do want to point out one good thing that has come with the merger for DM.
The ability to mix premium and saver awards on a roundtrip is a great improvement. I can now get the outbound for 12,500 miles and the return for 25,000 miles instead of having to spend 50k miles total.
The biggest problem with DM is the international upgrades which are TERRIBLE. The thing is, US is just stupid with this because without the opportunity to UG internationally on a reasonable fare there is no reason for me to limit my options to US for my international travel. This defeats the whole purpose of DM which is getting people to make you their first choice for air travel. I'm flying United across the pond next month so instead of getting say $1000 for a PHL-LGW run where I use miles or my certs to UG they are getting $0 out of me. I guess they figure if they sell GoEnvoy they can make that money back but that's a big if and a big strike against DM in my book.
Sean