I've used both OS's extensively. I think a large part of the perception of OS X being better than Windows is because OS X has a hardware standard.
Yes, and it's a huge advantage.
You can't really buy garbage grade hardware on a mac. People buy $400 windows laptops and when they suck they blame it on the OS rather than them being cheap.
The problem is you never know what's going to work and what isn't, when it comes to software upgrades and even worse, OS upgrades.
This relates to the above, which is that there is no hardware standard. This dramatically increases flexibility, but it also causes headaches for compatibility. You can buy name brand hardware to minimize this, but it only helps in terms of the actual OS you buy. Once you decide to upgrade the OS, you may run into problems.
I think the number 1 feature I like on OS X is I can run the exact same install that I have on my iMac that I have on my MacBook Pro if I want to. This simplifies backups greatly for example. I just backup the entire install and if I have a hardware problem I can simply just plug in the drive (via USB or whatever) and boot off that.
I think the biggest problem right now though is that some certificates on the Mac App Store have expired, so you can no longer run old installers. You have to re-download those installers.
http://tidbits.com/article/16302
That certificate expires in 2023, so if you re-download the installer now, you can use it for 7 more years. But in my case I actually store clean installs on backup drives. If I ever have to reinstall the OS, I generally just re-image it from a stored clean install.
BTW, this is another reason why although I like Macs a lot, I think the Mac App Store sucks.