Even Apple
who are notorious for their control freakery allow you to turn off the crap you don't like on Lion - such as unnatural scrolling et. al.
And normally so do Microsoft - you could even set Windows 7 so it looked like an old XP installation. However, it seems that in W8 they're forcing you to stay in the Metro UI without tinkering under the hood to find an obscure registry entry.
It really is a recipe for disaster for Microsoft. They *really* need to put a very obvious way to turn off the Metro UI and make it look like a start menu (i.e. make it optional rather than imposing it onto the unwary user) otherwise I know most corporates just won't roll it out - the retraining costs for W7 is bad enough - this will be way too much of a change and a step too far for most large corporates to stomach. (Hell - that's why most of us are still on XP!)
In a time when corporate IT training budgets are lower than the budget for tea bags, it's something that will just be sidelined.
It could even be a serious blessing in disguise for Apple, as it will sadly give the serial IT-Dept bothering wannabe Mac Adopters more ammunition to justify the shiny shiny Macbook Air they so crave.