Chartering in Spain
The sailing in the Med can be a little more challenging depending on the season. You have local winds like Tramontane or Mistral that can blow pretty hard and get the seas pretty agitated. I don''t know about southern Spain but elsewhere most nights are spent in a marina which is OK but does not compare to the BVI. The water is of course much cooler and the fish are almost non existent. On the other hand the social aspect of the trip is much more interesting specially if you have tiem to go inland.
I would also look at Croatia, much more "real" then the Spanish coast and the sailing appears to be superb.