Actually the acquisition was in Fall 2008. You can also try out the cloudkick CP for linode and AWS as well, from their CP you can use all 3 providers.
Prior to CK's acquisition by Rackspace, I'd say the main selling point is a common control panel experience for cross provider stuff. They were adding on monitoring as a pay service top as well.
I was suggesting it initially as a way to not suffer any pain with the existing Rackspace Cloud CP.
