There are many more episodes of TNG. I don't think I could watch episodes of TNG over and over and still love them like I do TOS. I used to see the TOS episodes 4-5 times a year and never got tired of them. I don't think TNG has that kind of staying power. So TOS goes deeper for me.
But when it was on the air, TNG was like my religion. My value system. LaForge and Data were role models for me in my job. My favorite parts were always when Data and Geordi would put their heads together to solve some mind-boggling space-time paradox, then present options to Picard. That team was so proficient, it never even occurred to Picard that his officers could ever screw up. The super-competence sank so deep into my bones, it was like I was being programmed.