The SunBird departs from dr and visits 5 islands and then back again (St Marteen, Dominica, Barbados, St Lucia and Tortola).
This cruise is called the Pearls of the Carribean and lasts 7 days, there are other cruises available.
The ship belongs to My Travel (I think), but if you do a search for "Pearls of the Carribean" or "Sunbird"), you should find more info.
As for past experiences, I don't know as I am on in at the end of March followed by 7 days in the dr, which I am really really really looking forward to now and it just can't come fast enough.
If you go to "www.holidaysuncovered.co.uk", ther are a few reviews on Carribean cruises.