Sync select is extremely handy. Often name and size are enough, but I do wish I could quickly and easily do a find uniques based on a fast hash (or a preference).
Or is there a script (or a feature) out there with an easy way to compare hashes for both panes that I've missed? Perhaps if one has a hash column set already?
Even if there is a script available (and yes, I could try and write one myself), I think having a more precise sync select would be useful, and would be found easily by users. I think being able to precisely compare panes for a corrupt file before deleting a side would be an often-used feature.
If you're not using Panes->Sync Select you should try it. Also Ctrl-K to compare single files works well and compares on the byte level.