Without reading what is likely mostly nonsense in this thread, I want to add my point of view on what SDN is for an applicant.
If you follow the advice given by DAT forum members, you will perform to your full potential on the DAT. You will not waste money on crappy resources.
If you follow the advice given by forum memebers on what schools to apply to, you will apply to schools that you have a good shot at and not waste money on schools.
If you follow the advice given by forum members about your personal statement, you will knock the PS out of the park.
If you follow the advice given by forum members about when/how to apply, you will apply early enough to get serious consideration from schools.
If you follow the advice given by forum members on interviewing skills/techniques/questions you will be well prepared for your interviews.
If you follow the advice given by forum members on selecting a school you will make a well informed decision with perspective that is unavailable from those in your real life that aren't familiar with the implications of choosing a school.
Basically, what I am trying to say is that I followed advice given by good forum members in all aspects of applying to dental school and I found myself accepted to more schools that I have fingers to count them.
Without SDN I can honestly say I would have scored 2-3 pts lower on my DAT, applied late, applied to the wrong schools, had an average PS and been lucky to squeeze out an acceptance or two.
Overall, if you have even a little common sense you can weed through the BS and use SDN for the valuable resource it is.