I don't think it's as significant as it used to be but I also don't think it's unimportant. If you have 100 candidates with equal hours, extra-curriculars and education, the one with more TPIC is most definitely going to have a leg up on the one with none. On the other hand, to say that TPIC is unimportant and going to a place thinking you'll swing gear for 2 years and get hired at a major is uninformed.