Well, I happen to have used both. And it all depends on your perspective. I would change my tools in a heartbeat to streamline the process for users or contributors. To me it depends on if you're user focused or technology driven. I think it's kind of akin to switching to git but insist that all merges have been done with perforce merge, because I think it's better in some way. Sure, it might be true, but do you really want to go against the stream to prove your point?
> And besides, if they want to they can just diff it on their own machines with whatever tools they like!
Oh yes, a very compelling argument when discussing workflow tools is to suggest local diffs. Bravo!