My assumption when a drive fails is that while there is a chance it is just a corrupt file, there is also a chance the drive is failing and the faster I get the data off the more chance I have of getting it at all.
You misunderstand. In your original post there was no indication that the drive was failing. To us (and to most of the world) a failing drive means that the drive is deteriorating physically. That does not seem to be the case in your explanation. BUT, if indeed the drive is having physical troubles, your assumption is correct, though a more likely course of action would be to clone the disk.
You can check the disk's physical health by running a SMART analysis (check the manual for details).
As it is a repair (with DiskPatch) can be quicker than a file recovery operation (like iRecover), and, if it works, the better choice; you can most likely use the drive as before after a successful DiskPatch repair. However, if a DiskPatch repair is not successful you will most likely need to use iRecover to copy files from the drive. Please note that a failed DiskPatch repair does NOT make matters worse (there is an undo, and a failed repair only means that the structure that was already damaged is still damaged, things do not get worse from that).
If you want us to take a look, post a support analysis log. The link was provided earlier.
Using iRecover is a direct approach, in a sense that it doesn't change anything on the disk (which is good), and thus the situation can't get worse.
The choice, in the end, is yours.