My background pre-merger was United. I'm really only seeing pre-merger Continental product starting back this August. After 4 flights on the "Continental" 2-1-2 767 business configurations I like it better than the pre-merger United product. I'm OK sitting backwards in a PMUA 2-2-2, but honestly, I think it's a lame design that looks like crap, and doesn't give much privacy. The lack of personal storage space and electric outlet placement don't help.
Last week on a 763ER MUC - IAD it was especially nice with the 30 seat cabin. It just feels more thought out, and at 6 feet 200 lbs + I have no problem sleeping. This was a "D" seat. Minor criticism - the footwells on the window seats appear to be smaller.
At the end of the day it's hair splitting; the important thing is to be in that class of service, whatever the configuration. Agree with other posts that the center D seats can be good for solo travel on the 767's that have them.