I've been struggling with some misconfigured appliances at work for the past couple of days, and I was getting tired of manually diff-ing things. On a whim, I decided to ask Google if there is a better way. Turns out there is, and it uses what I already know and love: VIM. Here's a command that lets you diff two remote file using vimdiff:
vimdiff scp://user@host//path/to/file scp://user@otherhost//path/to/file
This is going to save me so much time! I hope it is as useful to you all as it is to me.