I like them conceptualy much better than mast furling, since you can always just drop the halyard and flake the sail on the boom if a boom furler fails, unlike a jammed in-mast furler.

I'm sure they have their own share of problems.

The 3-4 month old Grand Solelil 54 in my marina had the main taken off last night to get repaired because the LeisureFurl boom was "eating" the sail. Probably half of the 3-4 months was in ship transport between some original sailng in Italy and arriving to the US and being motored to the marina. Not a good track record on that boat, certainly.