Re: Grenadines v BVI
I have done the Grenadines the last two years in a row (1st week of March). 2010 from Grenada to Tobago Cays and back and 2011 from Grenada to St. Lucia. It is a wonderful cruising ground. We always left from True Blue, Grenanda (Horizon Yacht Charters). I think if you are going all the way down to the Grenadines you might as well see Grenada too, it's beautiful.
2011 weather was very different from 2010. Seas were uncharacteristically large for the time, double what we saw in 2010 (occasional 20 footers when passed the lee of St. Vincent.) All the locals said it was rare. Tobago is gorgeous and worth at least one day, more if you've provisioned for it. George is one of the more well known boat boys and treated us great both years. The majority of folks will anchor in the marine park between Baradol and Petit Bateau, but we enjoyed anchoring in the channel on the north side of Petit Bateau. If the weather is like last year the current will be extremely strong - looking down through the trampoline while anchored you would have thought we were making 9 knots.
Union Island is a great place, check out Happy Island while you are there.
Bequai I could miss next time - while sitting in a bar having lunch some sort of official (cop or military) in plain clothes fired off a "warning shot" with a handgun about 6 feet from the back of my head at a drug dealer. They proceeded to arrest the guy on the front porch of our restaurant, while several more started climbing throught he roof of a tin shack next to us. I never felt we were in danger (the drug violence does not touch crusiers I believe) even during this situation, but it's all related to the drug activity on St. Vincent that I hope isn't wrecking a great crusing ground. Walilabou is neat stop on St. Vincent (the set from Pirates of the Caribbean is still mostly intact there), but check a cruising guide for the names of the two boat boys worth dealing with - it's incredibly deep and you'll anchor Medditeranean style to a tree on shore, so the help is needed if you're short handed.
I believe the only place outside of Grenada and St. Lucia we ever grabbed a mooring was Union Island.