Well, I really do believe the grass is always greener on the other side. Everybody is going to have something to say about any airline so it is hard to make the decision- which is why I started this post. I think it may be safe to say that the ug policy on DL is the worst. It is very expensive to get a flight that is upgradeable whether it is domesic or not. I am self employed and do have clients that pay for travel but I need to be reasonable if I am to stay competetive. So I lose upgrade points and am often stuck in coach over the atlantic even if there is room in f. Customer service is very inconsistant- they all tell you something different. Lately, I have very good service on the phone- at least they have been nice.

So, if my business takes off and I can come up with the funds to actually purchase B or F ticket, it seems that DL is lower for Europe trips. But I am not there yet so no need to be too loyal to them- they don't seem to be to me.

I have to say I always receive good service on the plane. That has been a plus for me.

I have found that AA fliers have more positive things to say about their airline than others. My next choice is NW (partners with CO- i think) and with KLM. Tempting because of my travel patterns. Both are better for west coast travelers because of SW and Alaska.

Those are things that influence my decision.
Hope it helps instead of confuses you.