It's not just aesthetics when the OS suddenly uses two major UI paradigms at the same time, switching between them with no discernible pattern. Users might learn the behavior or configure it away, but there's criticism to be had that goes far beyond "waaah change" in nuance.
For example, Windows 7 had one or two points of entry for any given task, Windows 8 has double that and half of those avenues can only give you 60% of the computer's overall capability.
But considering you can just do tweaks to make it more like Windows 7. By upgrading and doing that you can have the best of both worlds.
I don't regret upgrading to Windows 8 at all. Faster and I've still managed to get the old start menu back(which is the change I hated the most).