After speaking with TAs from all 3 agencies, I went with Crown. The gentleman was far more professional in his email and on the phone and appears to be someone I can work with. I got the AARP price, free ultimate beverage package promo and $250 OBC. Basically, that's $250 better than if I had booked with the line direct, about a 10% difference, and about $200 better than the general offer from the big on-line agencies. I could probably have paid less if I cared to work harder at it but I am satisfied.
The UBP is worth about $750, although god help me if I drink that much. It will be interesting to see how much the cabin price drops after the promo period ends July 31.