Its hard to determine if the frame materials are going to give you a significant difference between the two bikes WITHOUT also considering the components.

The A1 Mainpulated tubing is heavier than the E5 SLX Columbus tubing of the comp. Taken by itself, I would always pick the lighter tubing. Both will be plenty strong and neither really likes to be crashed.

The Trek 520 is an entry level bike (or at least it used to be), and not even in the same zipcode as the tricross comp.