Heaving to: We must have read the same books, I've always heard that full keels heave to better and create a better "slick" to windward to calm breakinig seas. I don't have any experience heaving to in a full keel but I know that my Islander 26 fin keel hove to rather nicely, only made about 1/2 knot of headway in 30+ knots of wind and while I never hove to in breaking seas it DID appear to make a nice windward slick.
I'm looking for a boat right now and I'm pondering the same things as you. I think I would feel better in a full keel boat making long passages.
Just my two cents.