After buying each NCAA since '07, I'm going to skip '13. I actually just found my '12 disc, and have been playing it lately, but the lack of substantial gameplay improvements over the last couple of year, coupled with an average demo for '13, and so-so reviews is leading me to not buy it.
On a related note, after not buying a Madden game since '10, I will be buying '13. The new physics engine and modes have peaked my interest, and, well, I have the itch!