I started using rackspace managed hosting back in 2005. This is before the “cloud” so they were all physical hosts.
Since then I’ve used them for a mix of cloud and physical for several different companies.
I have also build data centers from the ground up and managed a lot of services on AWS( amazon web services).
After being a customer of rackspace over the last seven years I have formed the following opinion.
If you think the cloud is “scary” and mysql gives you the willies then their support might seem like wizards but in reality they are not.
I found out from an inside source that many of their support team are high school graduates who are run through a boot camp.
Instant wizards.
I have had countless dealings with support where I found zero value in the exchange.
This isn’t true of their whole team of course, at some point you might get the contact information of someone who can actually help you.
When you do hold on to it.
A great example of this is their “managed mysql”, what it amounts to is mysql installed on a supposedly faster file system and backed up.
Of course its tuned which means the innodb_buffer_size is changed per RAM size.
Thats it.
If you really have a problem with MySQL no way are the bootcamp kids going to be of much use to you.
In both cases of physical and cloud rackspace has very good uptime.
Especially in comparison to EC2, and I’m not just talking about the big EC2 outages I’m talking about the day to day.
Its pretty common in EC2 to have a server freeze up and need to be rebooted or have it reboot on its own.
Of course when you decide to move to the cloud this is something you need to plan for but in the case of rackspace I can only think of a few times when one of my cloud instances ever went offline unexpectedly.
dodizzle 
Hi David, We’re sorry for the experiences which have caused you to form this opinion about our service and support. As a Racker, it really hurts to see this because it means that somehow we’ve failed you in our primary mission.We’d really like to hear more about your experiences with our service. If you feel like you’d be willing to share more details, would you email them to: help@rackspace.com ? You can also email me directly, just use the address I gave in the comment validation.Carl DavisonSocial Media Support Team | Rackspace Hosting@carljdavison on Twitter
I had some OK experiences with them – their managed services mysql team did make some good suggestions wrt to replication, etc, but we didn’t really utilize them fully(the team, not the suggestions).Their netsec team was usually pretty good – these were the folks I interacted with as we had a version 1.0 deployment of their hybrid cloud product. Ultimately due to costs the service was brought back in-house, but it wasn’t a *terrible* experience.