rhce exam
 

how rhce is tough

Being relative to how prepared you are, I've heard mixed responses to that question, though admittedly, most who pass with 100% put in the study time for it. I haven't yet taken the test, though I have taken its prerequisite so far. I would advise you to not just study, but also have a access to the OS, virtual machines on KVM, and be systematically be setting them up and running through as many excersizes as you can.

Here's a good blog I found on the objectives:
http://b.joaoubaldo.com/linux/rhce-my-study-guide/

Good luck.

were the ( for the USA ) ACT's or SAT's tough ?

Well if you know the basics, and am committed to your studies, RHCE is NOT THAT TOUGH ! I'm saying this noting the experience of many candidates who attend just an 8 day boot camp at our center. I've seen that the overall pass rate is >90% and have seen a good many person score 100% for both RHCSA and RHCE. (Believe me, we have more than 4800 RHCE certified Alumni who have studied at our center.)

Hands on lab work based off the objectives and those Michael Jang books worked for me. I have about a half dozen years of solid solaris/linux sysadmin/engineering experience but there were still topics that I really had to study on. I ended up scoring 300/300 on both exams. If you put in the time and effort and know the subject matter the tests are not that hard.

Like mrf009 says: the content of the exam isn't difficult.

I was really surprised although I had heard this is a renowned certificate that only this marginal skillset is required.

However! Do not misjudge it. Although the skills needed are limited IMHO, the exam can be harder than the objectives might look.
There is time pressure, you need to read the questions correctly and you have to be careful because a small mistake can take a lot of points.

I have seen numerous people with lots of experience with Linux marginally passing RHCSA. Not knowing what they did wrong(probably Redhat expects you to do something more in their opinion). On the other end I have seen people with almost no experience, following the course and ace-ing the exam.

As said in previous posts: you need actual experience, don't just study the book!
Use RHEL/CentOS and do each task until you are really familiar with it.

Further note that I would never hire someone because he has this certificate. However it might get your resume to the next round.

Good luck!