I never got more than 60% while doing mock exams.
Though I didn't feel quite well when I was dealing with the problems in the real exam, I still got the highest score I ever had.
I feel that some of the questions in the real exam are quite different from the mock exams. Some of them are very obvious and some of them I rarely saw before. And the time is very limited too.
After all, I had cleared it! I'm quite so happy now
I spent about 2 weeks preparing for 141 exam. Before that I knew nothing about XML
So to the ones who want to have the 141 exam and are not very assured about yourself, be confident enough to have a try.
Confidence and hardwork, plus a little bit luck, you're sure to succeed!