If I didn't hate M$ from the bottom of my heart already, then this would be enough to tilt me.
First they kill the only really working Linux version in the 4.x series, then they want to replace the 7.x abomination with the dog-ugly 8.x. I would be ashamed to admit I am working on this product if I was one of the devs.
(Exception to the rule: Their Intellimouse is nice, even more so the new Classic one with higher DPI. But then again, that is a hw product...)