I went with
St. Brendan's Isle in Green Cove Springs, FL. I read good reviews on them, liked their web interface for seeing my mail, and chose them.
However, if you're also using them for your residency- know that insurance (auto and health for sure) rates can be impacted by what zip code the mail service is in (and thusly, what you use for those policies). I had a friend who cross-referenced the Florida mail services and found which was best for he and his family.