Yes, policy is the same...free "whatever" drinks.
I have been on both ships. Both are very nice.
MY opinion:
Service is a bit better on the Diamond.
Food is better on the Diamond.
Amenities are slightly nicer on the Diamond (haven't been on Windstar for 10 years or so though)
However, the sailship aspect of Windstar IS nice. It is really quite a sight, when you leave port, to see her unfurl her sails.
THAT all said, I know you said don't look at cost...but I have to say that you get a better "deal" on the Diamond.
I don't think you would go wrong with either. They are both unique ships and experiences.
Sheri