for what it is worth, I will speak as an end user of linux, I use Centos, and have never used RHEL. Primarily because in looking for the type of Linux I want to run, I have changed multiple times from Fedora, Open Suze, Centos, LinxMint, and I like the freedom of changing with out costing anything. This being stated I have contrinuted donated funds for the use of Centos.
I have returned to Centos because it does install on my dell 1501, and I can easily configure my wireless card, and it works with the video card installed. Non of the others will work, I can't even get to command line, I get a gray streaked screen.
I do however think that supporting RHEL is important because of what it means overall to the Linux community. I dont have a windows run computer in my house, I have 4 computers running different versions of Linux and 1 Mac for my kids..who will be running linux next year.