I have a Mott flail Model 72 ,circa 1960 (that my dad bought),that I totally rebuilt three years ago. Its a solid mower and parts are still available(Mott is owned by Alamo now).I use it to cut my entire yard (1 1/2 acres)being pulled by a '58 ford 601. I keep it set low, like one inch. My yard looks like a carpet when I am done. You will need to use limiter chains to stop scalping, and sharpening knives is an all day affair. I have two sets of knives to save the straightening and sharpening for rainy days. Flails are not a rock happy mower, one good sized rock and you will be leaving a poorly cut strip that looks terrible. You will need to change cotter pins, and some clevis pins while changing knives. I swap knives midseason and grease every time its used. The days of spending 4 hours on the John Deere 38 inch tractor are long over...it is used for trimming now.If you do get a flail add (if there isnt one) a strip of rubber on the back of the mower in case it throws a knife. I found the missing ones I lost last year sticking in the side of my oak plank barn. Motts were known as "hammer knife mowers" from what I read they were the first to build them before everyone else jumped on the bandwagon.