The braze on's are the little metal fittings brazed (welded) onto the frame that guide and hold the cables. Because there are no derailleurs only a few are needed on a single speed for the brakes. Frames looks much "cleaner" without them.
i would definitely NOT pay $900 for one
IMO it is a fair price for the features you get. Retail is
maybe $100 to high, but a dealer would possibly work with you or give an accessory allowance. I'm not aware of any all road/weather bikes that have the flexibility and fender/tire clearance that it has.