Win7 is essentially what WinXP was a few years ago; it's not perfect, but it's familiar and it gets the job done and it stays out of the way (most of the time). As a user, Microsoft has to offer me something significant if they want me to spend time learning something new, and I've not yet seen it.
Windows 10 is to Win 7 what Win ME was to XP.
Re: Privacy: Maybe not directly a privacy concern, but one of my biggest issues with Windows 10 (and 8) is how many things are now out of your control. For instance, you can't disable automatic updates or the built-in antivirus for more than a short while. Given that, it's easy to imagine Microsoft pushing out a privacy-invading setting that you have to manually opt out of, which you won't do until you know about it.
I wouldn't say I barely tried it; I've had it installed since December and used it full-time for about a month before dual-booting Linux (and I still use it for gaming). Maybe I wouldn't be so frustrated with it if it didn't regularly freeze for several seconds at a time, because that's really the biggest issue I have with it (and I know I'm not the only one), but I'd say I gave it a pretty fair shot. Aside from losing access to a couple programs (which is why I dual-boot), I'm happy with Linux Mint.
That's probably from the built-in spyware and forced upgrade processes that run in the background.
I haven't had any significant problems with freezing and boot times.
I am a little biased as I'm doing C# MVC so I'm using Visual Studio, I think it's all pretty great.
You do have to get used to the new control panel, but all of the old panels are still there for you to use (I am nearly 100% sure), but it's not really _that_ bad. You get used to it.
I run Android on my phone so I'm pretty sure that overall I have no real privacy from any agency that really want to get in to my business... oh well.