We've been using RHEL as our standard Linux for over five years. Initially RHEL5 64b WS, then RHEL6. On the plus side, RHEL is almost always embraced by our CAD and CAE tool vendors as a supported OS. On the minus side, the libraries are as old as the hills and we really weren't feeling the love of sending $200/machine-image/year to Red Hat for this configuration grief. We had noodled in earlier versions of Ubuntu and had some mixed feelings. With Ubuntu 13.04 this past summer, I tried it again and it was just great: everything "just worked". We didn't even have to muck around with GPU drivers. What used to be a half day project of dependency-hell installed in one apt-get. Wow! I don't think of us as OS-bigots; but the understandable contrast between the library hassles we had with something as old as RHEL5 and didn't have with an OS as modern as Ubuntu 13.04 was just too much to overlook. We've started to let our RHEL licenses lapse; just keeping around a few frozen RHEL5s and one maintained RHEL6 so we have them in shop. But unless a client or application needs some other Linux; it's Ubuntu 13.04 in our shop this fall and going forward.
Jim Kulp at Parera did us all a solid by refreshing the OpenCPI mainline to build cleanly to Ubuntu 13.04 as well. Nice! He pushed those changes to the OpenCPI GitHub repo this evening. Thanks Jim!