I just rented one of these to do about 300 sq feet of white birch plank flooring. I've never used a floor sander before, and I've seen a ton of my friend and family screw up their floors with drum sanders. Part of it was inexperience, and part of it is the poor quality of the equipment that some of these places rent.
In any case, I ended up renting the U-sand (http://www.u-sand.com
) from Home Despot for $42 a day. They only had up to 120 grit paper in the store (made by Norton). I read that birch should be sanded to 180, so I had to order paper, and I also had to order the buffing pads for in between coats. The company that makes the sander also makes the paper for it, so I ordered their brand. I got 40, 80, 120, and 180 grits, and buffing pads. Their paper sucks. Bigtime. It clogs easily, and takes forever to cut. I went back to Home Despot and picked up some of the Norton paper. It cut about 5 times faster and didn't clog up. Buy the Norton paper if you can. I only used the Norton paper for leveling, 36-grit. I used the crappy Cherryhill paper for the rest.
300 sq feet took about 12 hours of straight sanding. This thing is SLOW. But, it really does a nice job, and the fact that it is so slow basically guarantees that you won't screw up your floor. I found myself having to ride around on top of the thing to make it cut fast enough in some spots. You basically have to manhandle this thing around if you want it to do any real work. Every muscle in my body ached the next day.
As far as the look of the floor, it's awesome. Looks perfectly flat when the finish is dry (Satin Traffic). When it was wet and shiny, some of the reflections of windows and the fireplace were slightly distorted, but not much. It turned out better than the floor in the rest of the house, which is the same wood and finish, but was done by a professional.
On a side note, the $80 a gallon for the Bona Traffic... totally worth it. I don't think I'd ever put anything else down. I can't see why anyone would ever do this much work only to put down some crappy finish from Home Depot or anywhere else.
I'll get some pics up soon, the final coat is currently drying.