Everybody who speaks well of Rackspace raves about their excellent support. On the other hand, people who hate them seem to have complaints about their support. As for me, Rackspace has been far and away the best web host company I've ever dealt with.
My husband and I have been with them for about six years now and have only had one issue with them. That was the power failure that took out their data center for a couple of hours two summers ago. Other than that, they have been completely reliable and professional in every way. Over the years I've had to contact them for various things and it's never been a problem reaching them. I called them on the phone, used the chat system, sent support tickets, and even contacted them on Twitter.
If I have any complaints at all it would be in the area of price and billing. They are a little bit more expensive than other companies offering the same services. But I think for the level of support you get, the price is pretty fair. Their billing system is sometimes a little screwy though. I think I've had to dispute my charges two or three times over the last six years. Thankfully, I was able to resolve the issue with them on each of the occasions.
Overall I am very happy with the service I received from Rackspace. I recommend them every chance I get.
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