Oooh, big can of worms.
It's interesting. There's only been one or two counter-arguments... (which is to say, relatively close to none.)
Most comments can be summed up by the stuff in the wikipedia article:
Criticism of Microsoft: http://en.wikipedia.org/wiki/Criticism_of_Microsoft
Yes, there's actually a wikipedia article criticizing Microsoft.
But in short, "Bad business practices" and "Shoddy software" have been the most common complaints. There's also several "We hate Microsoft, 'cause we spend so much time clean up after users due to Microsoft crap." I understand those complaints~ =^^=