I bought my Zune 80 from Zune Originals, and started off with the 2.2 firmware.
I am left handed and primarily use my right hand (thumb) to navigate my zune pad. At first it seemed like the zune pad was biased towards the left. When I say that I mean that even if my thumb was slightly towards the middle of the pad (but definitely on the left side), a press of the pad would yield a middle-button register. On the right side of the pad, I could be far to the right, middle/right, and it would always register a right-button register, as I thought it should.
Over time though (a couple days to a week), it seemed like either I was getting better at using it, or the device somehow learned my tendencies, but I no longer have this problem. Pressing left on the zunepad yields a left button press, even when I'm not far left on the pad, just how I like it.
Besides that issue in the beginning of my 80's lifespan, I love the zune pad. I mostly use tactile, but the touch is great for scrolling long lists of songs, and even for scrolling down items one by one. I'm very impressed with its sensitivity/resolution.
One thing I do find as an issue with the pad is its left and right scroll sensitivity. Scrolling left or right (Swiping my thumb/finger left or right on the zune pad) does not have the same responsiveness as scrolling up or down. Granted, I mainly use tactile left and right button presses to scroll left and right, but I thought I'd report that "issue" in case others liked to use that method.
I also recently learned that the zune pad is comprised of just one button, with the touch sensor determining which "button" is being pressed. Pretty cool.