I try to avoid boats with furling (Mast that is) mains for a couple of reasons.
1) Like Nolatom - takes away many of the things that helps shape & support the sail. It's a big compromise in everyway & never seems to pay you back for what you give up
2) Preventing jams - take care when you unfurl (should be controlled as you roll out) & absolutely when you Furl.....proper tension creates a tight roll which hopefully will prevent a jam................fingers crossed.......no guarantees!
Agree with Nolatom - the outhaul is the best way to flatten the sail ......make sure you don't have lines ie; topping lift, etc at the end of the boom restricting the clew/leech of the mainsail as it is being pulled all the way to the end......there should be a mark / tape showing the proper point................find that the outhaul & other lines plus cleats, rollers and other line handling attachments cause lots of friction vs the simple Halyard hoist. So make sure you check all that out before you leave the dock.
Boom Furlers seem to give the sail some of the things back that you lose with mast furling ie; battens & ability to drop the sail if a something goes wrong.
There are lots of horror stories with Mast furling mains but don't want be the bearer of bad news.