No problem mowing that stuff down, just be sure the ground is dry and you know what's in front of you. I've found that the biggest challenge is just being patient and going slow enough to let the mower do a good job of getting all of it. If you go too fast, you will have to go back and cut it again.
As for brand of mowers, they are all pretty much priced the same when comparing the same quality of mower. Heavy duty ones costing more because you are getting more. I have a light duty Landpride six foot rotary cutter that I pull behind a 35hp 4x4 Century tractor. It will cut anything I can run over with the tractor and it's proven to be a good mower. I have abused it pretty badly and I'm on my third gearbox, second stump jumper, six or seventh set of blades, second set of bolts for the blades, second tail wheel and my third driveshaft in the last dozen years that I've owned it. If I had gone for the heavy duty model, I probably wouldn't have spent as much time wrenching on it, but I tend to go with bad judgement while out there and put myself into situations that I know I shouldn't. Sometimes I get away with it, other times I'm walking back to the house to get the backhoe to pull myself out and drag the tractor back to the shop.
What I like about the Landpride brand is that I can go to any Kubota dealer and get the parts from them, or go online to Messicks.com and order them from them. I think that I would destroy any brand cutter, and what's important to me is being able to fix it quickly.
Eddie