I also have some outstanding reservations about the Touch Bar that I’m unable to test, specifically around aging.
I’ve already experienced hang-ups and glitches (hang-ups rarely, glitches quite frequently in Safari) with the Touch Bar. I worry that it’ll grow slow and unresponsive over time, as the MacBook Pro, like all computers, inevitably dulls with age. I don’t mind digital brightness and volume buttons now, but if in three years I can’t immediately mute the auto-playing video ad that just started blaring into my headphones because the button has become slow to respond, I’m going to be frustrated. Obviously there’s no easy answer to this concern — I asked Apple; it declined to comment — but it’s something to keep in mind if you’re considering buying generation one of an experimental product and plan on hanging onto it for several years to come.