We had a very enjoyable cruise with Windstar in February out of St Martin. As previous travellers with Star Clippers we were interested to see the differences between the two.
In terms of cabin we had superior cabin on Windstar - which is actually two standard cabins knocked together, bringing the benefit of two bathrooms, and two separate wardrobe/dressing area which felt a real luxury! This cabin was very well appointed, with lots of useful storage, and was very quiet. Star clippers Deluxe cabin is very compact, but comes with the added plus of a bath, and balcony.
In terms of dining, I would say the food was superior on the Windsurf, however the service in the restaurant was variable. If you ordered side dishes, they often did not arrive to coincide with the main dish - and often we had to chase them. One final major down point was that the main restaurant was very cold. We were in the caribbean and had packed accordingly. All the women were shivering under thick cardies (if they had thought to bring them!) or pashminas. Despite several complaints there was no improvement although they did try to sit us in a warmer section. This boat has recently been refurbished, it does not seem beyond the wit of man to achieve a more convivial temperature. The bar area was equally cold, which may explain why it was very quiet. Thankfully there was a smaller bar outside at the back, where we sought refuge most nights. There is an outside restaurant which was very good.