I am looking at updating my 35 foot JD flex head to a JD 735 flex Draper, is it worth the cost/Maint

Yes, definitely worth the upgrade in my opinion. We went from a 630F to a 735FD this year. Larger harvesting window during the day, less header loss, combine was more efficient and had a better tank sample because of the consistent feeding. One of the more noticeable equipment upgrades we’ve made.