Personally my view of Windows was tainted by what they did for me between about 95 and 2000, spent half my life with the side off, downloading 3rd party drivers and removing spyware.
2 Imacs, a Powemac, a Mac pro and several Macbook pro's later i'm glad I took the plunge back in 2000.
You are to a degree paying for a brand but within that brand comes some brutal strict quality control and despite a few complaints a very stable and reliable product that will be like that trusty favourite hoody that always does the job.
Sure a Moped will get you to work and back every day but a BMW will be so much more pleasurable and after £30k miles the moped will be going to scrapyard while you can get half your money back on the BMW.
Buy a Macbook pro and look after it then sell in 2 years and you will get half your money back, try that with a knackered Windows machine and you'll be lucky to get 10-20%.
I mean you are asking on an Apple forum which to choose so there is likely to only be one answer but I do believe in this case you get what you pay for.
I did buy a cheap Windows machine and use for 3 months earlier this year as a stopgap and it has come a long way since the older versions but there was still issues where things just didnt work as they should and just a slight feeling that it wasnt quite finished, not to mention that god awful block desktop thing. The trackpad was terrible also, the Macbooks trackpad has to be used to be believed
Overall I believe the OSX experience is better than that of Windows which for me along with the investment issue is the defining factor.