Some additional points from a mixture of people I know at the firm, personal experience, and research you could do from the outside looking in:
Grades matter but fit matters more. In reality this means that grades are practically necessary but not sufficient. There are more than enough applicants from the best schools to be selective on more than just grades, which is why people with 4.0+ get rejected. Those who don't have the grades probably won't get an interview unless they blow away an on campus interviewer or have an inside connection at the firm.
School preference is not in the order of the T14/15. Some schools have a much stronger pull at W&C, particularly local and southern schools. UVA, Duke, Georgetown, GW, and Texas send far more than Columbia, NYU, Michigan, Cornell, Northwestern, etc. It was rare to have an NYU summer but in most years there were a few Texas summers, 1-2 GW, many UVA/Duke/Georgetown.
When you interview, if you get one, emphasize love of litigation. Be humble about accomplishments and able to speak to out of office interests while demonstrating substantive intellectual curiosity about the law. The dream interview subject will not brag about grades or law review, will have insightful answers or observations about interesting cases from clerking, and why those legal issues were challenging, and should have some hobbies to discuss. The firm is very competitive to the outside world but wants collegiality in house, so people who have that kind of attitude (or learn it from military service or sports) are preferable.
Salary discrepancies are significant compared to the Cravath scale. Associates earn 25-30,000 less as third years, second year at the firm if coming off clerking, 50,000 less as fourth years, 70,000 less as fifth years, and the gulf increases for seniors, around 80-100,000 less each year as a senior. It's not just 10-15,000 a year and is significant both in absolute and percentage terms, so may not be the right place if you want to make the most money in your first 5-6 years of private practice.