I have no idea how many people submit portfolios. Also, I was never able to pin down before how often they reject applicants with qualifying scores, if ever. I am guessing from what I've read that in general they cast a pretty wide net, but what do I know? I vacillate between feeling like DS is a shoo-in, and feeling like we have no chance. But I'm a nervous freak.
I have seen plenty of portfolio applications get accepted, but also some that are rejected. Having a portfolio is one of the basic criteria, even though obviously subjective, no? And I can see how a portfolio could be stronger than test scores, e.g. a 3-year-old demonstrating her working time machine or something.

Some of the portfolio entries might happen because someone qualified only on IQ or achievement even though they also tested the other-- but there seems to be a fairly common bunch that use a portfolio because they don't want to spend the money on another round of testing and just have the one type of results, for example because a school system only administered achievement testing.