When I fist bought my land, I have very limited experience on a dozer. Then I did some work with a dirt contractor and he showed me how to run his JD 450G dozer. It's around 70 hp and small enough to move around wtih a one ton truck and trailer. It's allot bigger then those mini dozers. He uses it for building pads and cleaning up existing roads.
I had it at my place for awhile to clear some roads and open up a few areas. It was pretty much useless. It could take out decent sized trees with allot of effort and moving of dirt, but otherwise, it was only good for small saplings and brush.
Once I got the stuff on the ground, it was very difficult to move the piles. The piles weigh allot and are awkward to move alont. The small dozer didn't have enough weight or power to move very much at a time and it took forever to just get a small area cleared. At the end of the day, I really hadn't accomplished very much.
My fear is that a smaller dozer will be just that much lighter and more dificult to get anything done. For what you will pay to buy one of those little dozers, you could hire it out for half the price and have it done much, much better by a guy with the right equipment to do the job.
Do you want to spend allot of time not accomplishing very much, or get it done and move on to other projects? I'm a do it yourselfer to the extreme, but sometimes it's just cheaper to hire it out.
Eddie