I have had a 520 for a while now. I have put about 3500 miles on it in the last year or so, most of them commuting. I did change the rear rack to a Jandd, and put on some SKS full-fenders. The gearing is adequate for me, but I have been on the lowest gear riding fully loaded up some steep hills. I have also been up to 40 mph and still pedaling, so I decided not to change the gearing from stock.

I still have the stock wheels, but broke a spoke a few months back. I changed it myself (first time!) and everything has been fine since then. I also have the original tires, they probably have a few hundred more miles on them. I have gotten three flats over the 3500 miles. My brakes are still fine, and I have had to do minimal maintenance thus far. The 520 really is a beast, and hence heavy, but I have absolutely no worries about it when riding fully loaded. I think it actually handles better with some weight. It's actually perfect for around town commuting.