Typing at 15hz would be miserable (personally).

If the delay is consistent, it shouldn't be too bad. I spent 3 weeks on a business trip to Europe, when my devserver was in Sunnyvale, and did all my editing via ssh as I usually do (in joe, not vi, but pretty similar) and it was mostly fine --- I do recall doing some tunneling to reduce the latency a bit though. It was not as fine when they sent me to India with the same development setup, so there's a limit... But it's closer to 200ms than 100ms, so 15hz should be ok in my mind.