Hi Joyce,
While Ko Ko has answered most of your questions, I will try to add to those answers...
Are the SCMAD simulator's questions close to the real exam in terms of format, topics, tone and difficulty?
We (Siva and I) have tried our best to keep the questions as close in all terms you have mentioned to that of the real exam. This is based on our experience with the beta exam, which both of us participated in (and passed

)
As no books were present during the beta phase (not even now), we have taken most of the questions from the specifications themselves and maybe a few from books and articles that we have read.
For people who have tried this product and taken the exams, are their exam results close to the simulator's results?
We really hope so! Again, we kept in our mind the actual questions (not verbatim, of course) while preparing them and hope that they more or less reflect the real exam. In my opinion, the simulator's questions might probably be a bit tougher (not too much) than the actual exam. We have added some bonus questions (questions that are really easy) much like the real exam.
But as Ko Ko pointed out, we haven't heard from exam takers yet. I guess they are all seriously preparing for the exam
Btw, how come all the whizlab products so expensive? I think the "Unconditional Test Pass Guarantee" may not be good enough to convince people to purchase the products. IMO, it's more difficult to fail than to score well.
For obvious reasons (as Ko Ko mentioned), I leave this part for the WhizLabs marketing dept.
Best wishes for your preparation.