Interesting thread! When I was purchasing a tractor I too was interested in a flail mower. However, I couldnt find anyone who would recommend them. The reasons were high initial cost, high cost of up keep, not as good a cut as a conventional mower. What I could never get an answer for was what are the high up keep costs. No one I talked to could answer that one. So, what are they?
It seems that flail mowers would be more flexible than rotary types b/c w/ a changes of blades (or hammers...is that what theyre called?) you could have a mower suited for a wide range of situations.