I am not expert but here are my opinions:
Instead of rankings, think in terms of tiers. While Cornell maybe only a few spots ahead of UNC in terms of overall ranking, Cornell belongs to the T16 tier (i.e. Duke/Ross/Darden/Yale) and sometimes top 10. There may be a drop off in terms of quality of employers recruiting between the T16 tier and the next tier. It's like the difference between a GMAT score of 690 and 700, while the difference is small, it's more noticeable than the difference between a 700 and 710.
Internationally, there is no doubt Cornell carries more weight. It's no Harvard/Princeton/Yale, but it's in the same ivy-league category as Penn/Columbia/Dartmouth/Brown.
There is a youtube video called "This is Cornell" you can watch, it's a pretty good video.
But Ultimately, the you know yourself the best and make a decision that you will feel comfortable and happy with

Congrats on getting the full ride at UNC and admission at Cornell.