I got one for my BBU.
Nice rack, holds all the weight I can jam into it, big bag of cat litter, groceries, and 18pack of beer. 30+ lbs.
You would need really big panniers to overload it.
In NYC, almost any bike shop that deals with QBP (Quality Bike Parts distributor) can order one for you.
Some however may not want to take the time for a $30.00 item, thats about what I paid for it in Baltimore.
Rotor size is an issue, it will barely work with a 180mm avid juicy five disc, 160mm should be fine.I changed barkes from stock to the juicys and part of the pannier frame touches the caliper almost about 1 mm clearance.
Seems to be a pretty solid and well made rack, my .02 worth.