Atlgared, imagine it's me, Blamona!
Of course I've been to SVG too. I like island hopping, and while I did it, it was hard to do. First I'll tell you what I did, then I'll tell you what I think. (and if you get tired of me answering, I'm not offended!)
Flew into St. Vincent, took ferry to Bequia. From Bequia, i actually paid a fishmen $100 to take me to Mustique for the day! I wasn't crazy about Bequia, (I know there are fans out there, it just wasn't for me) so I went back to St. Vincent. From there I flew on a small plane (really small) to Canouan, where I stayed for a week. From there, I did day catamaran trips through the Grenadines, Mayreau, Palm, Union, Tobago Cays, even Petit St. Vincent and tiny Mopion. (Mopion is awesome, a big sand bar with an umbrella, umbrella changes spots with the tide. While there, a magazine was writing an article, and he wrote me in!!)
On another Grenadines trip, we went from Barbados as a day trip, fly to Union, took catamaran to Palm, Petit St. Vincent, and Mopion, was suppose to go to Tabago Cays, but got caught in a squall.
All 3 are different from each other: Anguilla is upscale, expensive,good food, quiet, excellent beaches. Playa del Carmen is fun, cheap, good food, good shopping, crowded active. SVG are more of adventure, there are some nice places to stay, but most cater to sailers. Tobago Cays are beautiful (they filmed Pirates of Caribean near by) Mopion is really cool, and the view from Palm Island is goregous, like a mini Bora Bora. If you went to SVG, I would stay at Palm Island, and they will offer day trips through some of the grenadines. Knowing your tast in beaches, you can skip Bequia and St. Vincent. American Airlines offers specials with Palm island, usually $200 when you stay there. My opinion, but SVG is probably for a more seasoned traveler, for the same kind of trip, to "break you in" you might want to look at Virgin Islands. (Okay, I just confused you more!)
I hope you don't get tired of hearing from me!