Most schools will probably not care if you take it 2 or 3 times. I think it's also important to keep in mind that 700+ scores get dinged all the time. I would say that someone with stats generally in-line with school averages will probably be admitted at rates equal to the school's overall admit rate.
So, let's take someone with a 3.3 GPA & 710 GMAT, along with average work experience an extracurriculars and reasonably good essay and interview execution. If this person were to apply to 5 top 15 schools, he would probably be admitted at 1 or 2 of them. That means this person would likely be rejected from 3-4 of them.
So, people with 700+ are rejected all the time. That's why few people apply to just one school. Most apply to a range. This doesn't mean that the GMAT is not important; quite the contrary the fact that 700+ scores are regularly rejected makes it all the more important to do well on the exam. If the above candidate had a 660 instead of 710, he could reasonably expect admission to 1 in 10 maybe, rather than 1-2 out of 5.