I know they are expensive but let me tell you I wouldn't trade my pair. I use these (I have the previous model) more than just about any other tool I own. Any time I am on the floor doing any kind of work I wear them. They are ultra comfortable and IMHO worth every penny.
I am torn, quite frankly. I love the fact that I did my kitchen in a weekend (while also participating in Ham Radio Field Day, no less) and have a floor that has a much tougher finish than anything that I could have put down, but I just love a properly sanded and finished floor and how it seems to be of a "whole".
I've done both ways, with fir, oak and maple (Gawd, I'm getting old!). I traded off this time, but when I replace the w/w upstairs, I am gonna go with a proper oak floor that I sand myself (or get my young son to sand to teach him some humility). Those of you who have seen the last sanded floor I did before I moved here can appreciate!