I have Jandd Expedition front and back on a 520 as well. They're good. They've held up to a couple of years of hard utility use, and touring.
I especially like the front rack, with the shelf. That shelf makes the whole front much more stable than it would be with just a bar. I don't normally put things on the shelf, but I would, I guess, if I needed to. I wouldn't do that unless I were *sure* whatever it was was going to stay put. I get really uneasy about loose things around the front wheel. But it's nice the shelf is there if I want to use it. It also keeps water off of you by itself, without fenders. If you're going to ride in the rain, though, real fenders are worth it to keep the water off of your downtube, and bottom bracket.
Hardcore tourists prefer the more expensive steel racks, but having used these Jandd for a couple of years I'd take a long tour with them.