I was considering a Roomba but after reading this I've decided it's simply not an option because I own cats, and this is not a risk I'm willing to take.
If your cats regularly (or even irregularly) poop on the floor, then yeah, I wouldn't risk it. If it only happens in one area of the house, then you can set up a beacon to keep the roomba away.
It hasn't been a problem with our dogs.
They've pooped on the floor exactly once during a time when there was a lot of change and one of them was stressed out. I'm actually more concerned about regular old vomit or a hairball than poop, but even the possibility of cat poop spread all over is enough to turn me off to it.
I had three cats and an older refurb Roomba and it worked fine. One was a longhair and they all shed quite a bit.