I can tell you why I am doing it. Stateside, Red Hat certificates are equal to CCIE in status; in that they are well respected. Unlike other certifications which are multiple choice, the Red Hat certifications are proficiency based and they also include a time crunch.
As one recruiter told me, when a team is interviewing an RHCE, they know (s)he knows what (s)he knows. He knows how to fix a system and if he is unfamiliar with something he knows enough to leverage the documentation.
My purpose for earning my RHCSA wasn't for anything directly work related. I didn't need it to get, or keep, a job. In fact, my job doesn't require it and there wasn't any benefit (in terms of advancement or pay raises) for getting it.
I did it because I teach at, and lead, a Red Hat Academy at a local community college. I wanted to go through the same experience that my students will be facing after they complete the courses I'm teaching.
I wanted my students to know that I don't just want to talk the talk, I also walk the walk.
Which means that I will also be taking the RHCE exam fairly soon.
There are several pros to taking Red Hat certifications. But the top one would be the hands on experience. Unlike other certifications, both the learning and the exam are practical. This gives the impression that you have acquired enough knowledge to handle the administration tasks in the field or in practice.
I attended a conference last week and one of the presenters was resposible for interviewing members for his team. When asked what he looks for on resumes, he stated "if RHCE is on their resume, then I want to talk to that person". Red Hat certifications are that highly regarded in the industry.
I agree with what has already been said. Red Hat certs carry a lot of wieght and are highly regarded.
If anyone doubts it, explain what you had to go through to earn the certificate - in particular how the exam is given, the performance based nature of the exam, the fact that there are no multiple choice questions (or questions at all, for that matter), and that it often does not matter how an objective is completed, only that it is.
Employers can be assured that a Red Hat Certified <whatever> knows their stuff.