Eric:
I have a Kubota 54" MMM, Bush Hog Squealer 480 (48") with 3" X 3/8" lift blades, and a Bush Hog 285 (1' narrower than Farmwithjunk's 286) with 4" X 1/2" lift blades.
The MMM clearly does the neatest job, and it will cut 1/2" saplings/brush without much problem if you slow down a bit. So if you are sure you will cut nothing bigger a MMM should be your choice.
But the Squealer 480 with 3/8" thick blades runs a very close second in neatness to the MMM when the blades are sharp. 1/8" in thickness and 1" in width does not seem like much difference, but is has a large effect on the results and the power required. A Kubota
B2400 (18 pto hp) runs the 48" Squealer easily, and I think it is due to the thinner and narrower blades because they require less power to push through the grass and are much easier to keep sharp. I have one 20 acre bottom that I sometimes let grow for a year. No real trees, but the grass is thick and the weeds are head high. The 18pto hp
B2400 with the 48" Squealer will mow almost as much as the 27pto hp
L2900 with the 60" 285, and I attribute most of that to the difference in blade size.
The Squealer is rated for 1" saplings, and if I take it easy it will handle 2" (at least it has for the past 8 years).