I did the RHCE a few months ago.
I can't go into specifics about the content as such for obvious reasons - it would devalue the certification if everyone knew exactly what was contained in the exams!
What I can say, however, is that I found it to be an incredibly challenging full day of exams. It's almost entirely experience-based and working on real machines. It encompasses most areas that you would expect - problem-solving, installation and configuration, security etc.
I cannot yet say how the job market has reacted to my having RHCE on my CV, since I haven't actually put out any CV's with it on... I have a reasonably stable job at the moment, and doing the certification is more of a 'just in case' thing. I would imagine that the RHCE is at the moment mostly recognised and appreciated only by employers who are really knowledgeable about IT and the market. However, I see this as a good thing since they're the sort of employers I would prefer to work with anyway.
Basically, I would highly recommend it. Make absolutely sure you are completely comfortable with pretty much all aspects of Red Hat Linux - I found what worked for me was working through one of the many huge books (like Red Hat Linux 7.2 Unleashed) whilst going over everything on my computers at the same time, and doing it as many times as it took so that I was sure I understood it!
Good Luck!