FWIW, I'm 5'6" with a a 30" inseam, and riding a 52cm Specialized Tricross. You may be happier with a 49cm Tricross. As you probably know, toe overlap is an issue with 700c wheels and smaller frame bikes. No biggie, but for some it can be scary. I definitely have toe overlap, kind of annoying, but I'm fine with it. The Tricross is a great do-it-all bike. So is the 520. Really try and get some test riding in. YMMV