I set my windows station as a dual-boot of Win 7 and 10 a few months ago. In my case, it's mostly for testing stuff, learning C#/F# on their proper platform (yes, I know about Mono) and getting some hands-on experience with those systems. The overall experience is neither appalling nor amazing. Both were thoroughly decrapped, and IMO I did my best to prevent suspicious network activity. There are no long-term plans for this box, but at the moment I have no reason to repurpose or wipe it clean.
I'd guesstimate that 90% of my work continues to be done on Linux or FreeBSD, so there's that.
EDIT: I'll likely preserve the Windows 7 partition, maybe a VM copy as well, after the final updates. At worst it's going to be a waste of space, at best I'll find some cool use for it, for a loose definition of cool that is.