(Note: I'm one of the folks who works at HashiCorp)

We don't have permission at this time to share some of our big users (we're working on approvals!), but I can say that that some very big companies you've certainly heard of and probably use right now have deployed Consul across every server. And Consuls deployment in just companies were working with is in the hundreds of thousands of machines.

At this point were very confident in its stability and it's well proven at very large scale.

If you're a big user and need references to other large users, email me and I'd be happy to set that up.