without repeating what others have said already....
there is a small nitch market, of companies creating blades and like for rotary cutters. that turns them more into a finishing mower. i want to say i remember some blades for rotary cutters that mimic the looks of regular finish mower "mulching blades" vs just a simple straight blade.
there are different deck styles as well more so underneath the deck. some decks are just box shaped. others have a "circle of metal" on the bottom side that is just a couple inches away form the blades themselves. i would imagine the circle, helps create a better "suction" effect to pull stuff up into the blades. and maybe causes stuff to be mulched up more, side effect most likely it takes more HP to keep the blades spinning.
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some folks just want to cut weeds down and live with the windrows. and more wanting to keep annoying stuff cut down such as stuff with needles, or small little trees, to other.
other folks want a bit more finishing cut.
other folks just need a plain old extremely heave duty deck and blades due to amount the unit gets used.
other folks might get away with a light duty deck due to not really using it that much to cut down small trees / bushes, and do more frequent mowing.
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i would advise not trying to drag something behind you trying to collect stuff. ((tried it once, i got about 30 foot and stopped)) like heck am i going to be picking up 100 piles of clippings.
www.tractorhouse.com there are various "rakes" for say hay to make windrows on purpose. so a baler can come along and suck the stuff up to make bails. if you actually want to remove the stuff. but seems a little excessive. vs just mowing more often.