If I were eyeballing two hashes to make sure they were equal, I'd worry about my ability to see near collisions (similar to [0]) the longer the hashes were. My eyes just start skipping ahead at some point, and would probably miss different-but-similar-looking characters in the middle.

But I think SHA-512 is resistant to near-collisions (sorry, I don't have a citation), and besides, one would probably best compare hashes using a script one understands.

[0] http://link.springer.com/content/pdf/10.1007%2F978-3-540-286...