Both have strengths and weaknesses - though Microsoft gets unreasonable bad press as noted above by having to support a vast array of hardware and the issues that sometimes causes.
In my view a 'clean' install of windows (without some of the horrible crapware that comes with nearly all name brand boxes) is usually really solid and hard to beat. The only times I have issues is usually where some HP/Acer/Lenovo(the worst) extras come pre-installed - they can be quite difficult to remove as well.
MS would do itself a favour if they somehow let a user have a 'clean' install - but I know the hardware manufacturers often get paid to include 'trial' products etc on their gear.
Same could be said for android of course - there are a few 'pure' android phones/tablets. But pretty hard to get the OS in all its stripped down glory.
MS has been taken to task a few times for 'monopolistic or anti competitive practices - but Apple seems to have mostly escaped this - not quite sure how.
Possibly as MS is one Windows, over many many PC manufacturers, and the likely goings on that a relationship like that could spawn.
Apple doesnt really have any competitors. Its competitor is not MS or Toshiba etc, its its own customer base, driving them to upgrade this year and not next year etc. In many ways it lives in its own world, happy to take customers off MS etc, but happy in its own world. Its desktop market share hasnt changed a lot over the years, they seem ok with that. No competition from other Apple manufacturers as there arent any