My husband and I just returned from GC and I thought I would offer my thoughts on some of the questions that keep popping up on this forum.
Security: There are private security people who are out and about now to supplement the police force. One night, we were actually followed back from Spiga to our hotel (Grand Case Beach Club) by one of these security officers. It felt safe to me - plenty of other tourists on the streets, no one seemed threatening. There is a bit of a dark stretch between Spiga and GCBC but, as I mentioned, there always seemed to be plenty of other people on the road.
Mosquitos: The first four days we saw only one in our room (which we killed) and this was after driving all over the island. I was feeling pretty confident so we didn't bother with the bug spray. On day five however, while eating at Le Tastevin, my husband got a couple of bites. He used the spray at the restaurant (everyone has bug spray - just ask) but he already had the bites by then. After that night, we sprayed every evening before we went out. (Never saw any on the beach - I think it was too windy.) So far, no signs of the virus.
Restaurants: You cannot go wrong here - every place is fantastic! We ate at the following places: La Villa, Spiga (ate here twice), Sky's the Limit, Le Cottage, Le Tastevin and Ocean 82. Went for drinks at Calmos Cafe and had dessert only at Il Nettuno. Plan to pay more cash than credit - many places offer the euro=dollar deal which is about a 30% savings, but only if you pay cash.
Les Mardis de Grand Case: Every Tuesday from the end of January to April, there is a street fair with vendors, live music and a small parade. We really enjoyed this - got some unusual souvenirs. It was pretty neat because it seemed to draw both locals and tourists. Atmosphere was very festive.
In conclusion, I would say don't worry about crime, try as many restaurants as your budget allows and definitely spray for mosquitos (even if you don't see them)!