Joined: Aug 2010
Posts: 12,728
Likes: 2,106
From: Madison, WI
Bikes: 1961 Ideor, 1966 Perfekt 3 Speed AB Hub, 1994 Bridgestone MB-6, 2006 Airnimal Joey, 2009 Thorn Sherpa, 2013 Thorn Nomad MkII, 2015 VO Pass Hunter, 2017 Lynskey Backroad, 2017 Raleigh Gran Prix, 1980s Bianchi Mixte on a trainer. Others are now gone.
I missed that you could keep the 520 when I wrote my previous post, thanks to Mstateglfr for catching that.
I would keep the 520 and put some paint on the bare metal, or perhaps you can find some nail polish that matches. And I would ride it, hoping that the crack does not grow more.
Plus, as suggested by Mstateglfr, take a Trek, but instead I would keep it so get one that you like.