Tedfroop
One eyed and left handed
Bettinardi's honey comb is supposed to get the face ultra-flat... "to ensure perfect flatness to within .01 of an inch" from everyhing I've read.
For me milling does change the feel, could be in my head, but it does. I prefer the feel of a deep milled face. Thats just me though.
I would think it would be more quantitative than that. Most milling would reduce the surface area of contact between the club and ball. That area on a putter is so small any reduction would affect the feel at contact.