I'm going to take a shot in the dark here and guess that you are referring to UNC and Vanderbilt. Though I may be incorrect. I considered both of these programs, and only applied to Vanderbilt for reasons of fit. I ended up getting in, and the funding was indeed very generous. There are two things I recommend you do, if you have not already. 1. Email graduate students at the public school and ask about teaching loads and internal sources of funding, or ask at visit day if that has not happened yet. Generally graduate students will be honest. You do not want to go somewhere that does not support you. 2. Chase down graduates of each department in your sub-field, and try to get a sense of placement. For instance, although NYU is ranked 23, they place graduates better and in higher numbers than many higher-ranked departments. This is an imprecise science, and it will depend on your sub-field, but I say it because Vanderbilt (if you are indeed referring to Vanderbilt) scared me off with a low placement rate. Few institutions place even half of their graduates in tenure track positions, but in my sub-field Vanderbilt had placed zero people in the past 20 years.
It sounds like you're between two excellent schools. Do your due diligence and weigh the intangibles--if someplace gives you an odd feeling, listen to you gut. Congratulations and good luck!