The most valuable feature is the package management. It helps a lot. I also like the support.
Red Hat is a Linux-supportive and well-managed offering. It helps a lot in terms of when we're working in production, it gives us the confidence that our packages are legitimate and genuine and we always have support available. It helps a lot. Red Hat Enterprise Linux gives peace of mind compared to other unsupported Linux distributions.
I also like Red Hat Satellite.
I haven't used Insights yet but it seems interesting.
The ability to patch Red Hat Enterprise Linux through Satellite is a huge contributor to mitigating all of the compliance requirements.
Red Hat Enterprise Linux has absolutely affected our security's uptime. None of the other distributions are nearly close to what you can get with Red Hat Enterprise Linux. Red Hat Enterprise Linux is something that helps a lot in ensuring that your secure application is up all the time and that you're not getting hit by vulnerabilities. It is an easier way for you to mitigate vulnerabilities when they're around.
The knowledge base is very useful. The only thing is that you need to have an account to get access. In terms of the content, the relevance, and being able to use the knowledge base to address things I've needed to deal with, it's awesome. For example, I was trying to add proxy configuration to the package manager once and if it wasn't for the knowledge base, I wouldn't have been able to do it.