Overall I've been a happy Rackspace customer for years, but we've had the same experience with Apache troubleshooting. The support ended at whether Apache was up and running. Beyond that we were told Rackspace considered it to be "application tuning"--which covers all the important settings that are used to manage loads and secure Apache. Luckily a development company we had on contract had a great Linux admin who could help us out.
From this perspective Rackspace definitely has not performed a devops role for us. Network administrator? System administrator? Yes, absolutely, and great support for both. But devops is where the application meets the server, and IME Rackspace has stayed away from that.
I do see the reason for it--what does Rackspace know about our application? It's not fair to hold them responsible for that. But it created a gap in our professional support.
edit: words