I just recently left my job at Microsoft, about 7 months ago. That said, I have nothing but mostly great things to say about my time there (2010-2014). By the time I got there, there was already the sense that even though we had huge market share on traditional desktop operating systems, that we were still far and away the underdog in many other respects that probably mattered more. Working on the dethroned Windows OS was an exciting and compelling thing. How do you stay relevant in a market that is rapidly changing without just outright copying the competition and while still giving it its own unique perspective? That's a really hard problem, and a really fun one to work on. Even though I know we didn't get it all right in 8/8.1, the excitement was all there and it was a really great ride.
Ask yourself if you would rather work for a big software leader that is resting on its laurels or for a company that knows it has some ground to cover if it wants to stay relevant, and then you'll know if you prefer the old Microsoft or the new one.
Robert Owen thought the same thing at the beginning of the industrial revolution some 200 years ago. Skyrocketing productivity was supposed to lead to a new age where a society could produce all it needed with little effort, and much time would be left over for leisure and pursuit of the arts. Instead, there were mass populations of over-urbanized, overworked, impoverished people. Turns out that when the means of production are owned by the few elite, innovations in productivity are more likely to marginalize the rest.
Ask yourself if you would rather work for a big software leader that is resting on its laurels or for a company that knows it has some ground to cover if it wants to stay relevant, and then you'll know if you prefer the old Microsoft or the new one.