Your score is good enough if you have a great application. Don't get too hung up on the GMAT score. The best thing a 700+ does for you is help the school maintain or boot their stats. The committees know well there is little difference between the performance in the program of a 700 student and a 650 student. With 15 years experience at big 4 firms, you will bring a wealth of knowledge to the table. This is what you should leverage to your advantage. Most b-school applicants are coming with 3-6 years experience, and most accepted students have 5-7 years. By doubling that, you in effect bring 2x the practical knowledge to team projects and case discussions. Harvard is largely a numbers game---even seemingly perfect applicants get dinged for silly little reasons. Make sure you are putting out 5-6 applications to be safe. You will have a great experience at any top school, so don't fret if you don't get in a few of them.