I took it also and passed on my first try. I had friends recommend that I take the thermo test saying the scope is narrower. I've done "machine design" related work every since college, so I stuck with that.
Two weeks before the test I took the ncees practice and bombed it, I figured out where my mistakes were, but it completely discouraged me. The tricks got me on simple problems. The week of the test, I had come to the conclusion that I would be retaking it. The morning session went fair, I think I had to guess at 2 or 3 problems. I fully expected the afternoon session to be harder. But when I had about 30/40 questions answered with no guesses, it hit me that I could possibly pass. Then as I finished the last problem at 12 min. til, I almost shed a tear. I didn't have to guess and got what I felt was a legit answer for each question. I felt really good leaving. 6 weeks of waiting shed a little doubt on it, but I was very happy to see the pass yesterday.