DDF is first rate for quality, lighting and poses.
Suzi is technically very, very good, but her stylists, IMO, are stuck in the 80's. I don't care so much for the rodeo, body shop, whatever....
Joannie Allum gets very intimate with the models, it comes across in the photos. There is always very tight cropping and the choice of models is always on the womanly side (as opposed to the skinny...)
Matti Klatt has stuck to the same Hustler style for too long...and his work gets PSd to death anyway...
Don't forget DDGirls (J Stephen Hicks)....he is more "glamour" style, but also has enough heat (single girl penetration). He also has very good stylists and seems to be the most experimental of the bunch.
:2 cents: