Originally Posted by farmmower
Haven't considered propane and not that familiar with it, probably cheaper to run. Re: the previous post the dealer says he sells very little of the 72" and I have ditch to cut out - think it would scalp and not be as maneuverable.
From your comment, I think you may have misunderstood or are not aware that the 3100 is available in several gas engine models. Larger wheels and tires, a bit heavier built etc. That would be the way to go IMO. If you want to stick with the two machines you listed, go with the Ferris. The Exmark will clump in damp or wet conditions if you ever have to cut in them at all.