I see people with in-mast furlers
wishing to change them all the time. Lots of offers to swap rigs
with conventional systems on various owner lists. In-boom is very nice and can offer almost as much sail area as conventional mains do. BUT it is very expensive to convert, and some systems still have problems. As far as in-mast systems go the sails blow out quickly if the boat is sailed in windy areas. Some owners do like them and end up relying on large headsails to make up the difference in lost sail area.