The group I run with has ran a couple. There is a few things you should know about them, good and bad.
Good: they are tanks, one of the most well built tractors out there. they go very well for a stock tractor if you tighten down the limited slip to give it more traction.
Bad: they have a worm gear final drive, which means they will not roll without the engine driving them. this really doesnt matter unless you are trying to climb a hill and the front tires start to come up. all other tractors (minus hydros) will roll back when you hit the clutch and the tractor usually wont roll on top of you. bolens not so much.
both of the guys that ran bolens flipped theres on themselves a couple times then went to another type of tractor. Bottom line is there rock solid, and good for flat swamp type mudding, but bad for hillclimbs/steep terrain