Am now in a position to answer my own question. Over the past several days, I have had occasion to contact technical support several times for a series of questions and actions involving at least two changes of server. Some of these questions were simple, and some very complicated.
Simple questions were answered within a few minutes, even the most complicated answers were answered within one-and-a-half hours.
One-and-a-half hours may seem a long time when you're the one waiting for a response, but when you think about it the service response time is really excellent. Anything within minutes to one-and-a-half hours is some of the best service response times out there. Well done to all involved.