It really depends on the person. In general, someone who is used to planing powerboats (faster, sharper motions) will likely do better on a cat. Others do better with the slow motion of a mono. And some are sensitive to heeling, others not so much.
Depending on the boat
and its roll period, I have to be a little more careful on a monohull sailboat vs pretty much any other boat
. The smooth rolling motion, especially going downwind will sometimes get to me if I'm focusing on something on the boat too much, although heeling is a non-issue and I do just fine beating upwind (despite having grown up as a powerboater).
Interestingly, at the dock
, my boss's Pacific Seacraft
34 and my boat have very similar roll periods (both are very close to 3 seconds). Both are monos, one sail, one power. Mine lacks the weight up top and down low due to the lack of keel
, but it's a significantly heavier boat overall and with a wider beam and hard chines). However, the roll on mine is a bit less comfortable, but also less nauseating to most people, particularly when working on something below, as it's more of a "roll quickly, slow down and stop, roll back". On the PSC 34, the motion is more of a slow, steady roll up to the end where it gently stops and reverses. The motion is smoother, which I (and some others) have a harder time dealing with.