Agreed. The MTFs don't lie; the corner-to-corner performance of the 100mm is far superior, and I would go even further and say the two show an appreciable difference in performance beyond even a 10mm radius from the centre. The level of distortion of the 100mm is also far better.
There are also differences that the MTF chart doesn't reveal, such as the level of coma (wide open the 80mm has gobs of it).
Anyway, the main thing is which you will be happier using, and the choice of focal length may ultimately prove more important to you than pure optical performance, especially if you will be using it hand held.