As Westie suggests, with a smaller main, shorter boom, etc. -- the single line system is easier to depend on.

I wouldn't do it myself because the adjustment of the system is a pain. Get a good reef in and adjusting the clew (depending on how much you need to flatten the sail, and other attempts to control the shape become problematic.

I've heard and (the few times I've been on someone else's boat with one) that the blocks are more complicated.

Ultimately, you need more line.

I wouldn't do it myself because when I tie a reef in under way, I really don't want to be HIHO (halfway-in-halfway-out) if something gets hung-up.

Do you have interal reefing in the boom? do you have blocks on the end of the boom? What size boat?