J...
Whatever you get... Get a SSD drive for your primary boot drive. A good quality one will allow your system to boot and programs to load up to 10x faster. It's simply a major leap in performance and will be the standard soon.
Not trying to talk you into to anything but I'll talk about the improvements seen on the Windows side ... much of which probably in comparison also applies to Mac as well.
Vista was a sorry version of Windows, much like Windows ME was. It's only boon was they finally got the 64b portion working pretty well allowing for larger capacity storage drives and it could access more than 4Gb of system memory ( which only 3.3Gb was actually available for the OS and programs to use ). Windows XP did have a 64b version but it was buggy and there were always little glitches running certain programs.
Windows 7 was the first decent OS MS had made that also supported 64b programming. It gained an order of magnitude in performance over Vista when MS pulled all of the DRM crap they'd put into Vista out of it. There were also other gains in other areas as well.
Windows 8.x wasn't as bad as everyone complained about under the hood... but MS saddled it with a crippled Start Menu that only supported touch screens well.. and left behind their keyboard/mouse users. It's improvement over Win7 was in a bit of a performance gain brought by MS finally starting to clean up the old code and removing some redundant calls to the various system libraries.
Windows 10 brings another order of magnitude better than Win7 brought. MS really got most of the gains by continuing the code cleanup they started with Win8.x. They also address a lot of the security issues that'd been plaguing them making it even more secure.
If you do go with Windows again... make sure to setup before you connect it to the internet. That way you'll avoid having to setup a MS Account, something many complain about since it forces them to always log into the computer. Also, if you forget your password later ( if you set one up )... it makes recovery a little easier since you won't need access to another
device with internet access to recover a lost password.
With what I said about Windows and how far its come, is likely the same or at least similar for a Mac. What you've currently got is pretty dated... whether you go for either... expect to see a lot of changes and once you get used to them, probably be better for it.