Now all PC's are on Win10, and no issues. I did have a couple of very small issues but easily worked through.
I also have 2 laptops(kids, Win7's) and my old tablet which used to be Win7 too. The tablet is a way underpowered Atom thing.
I've never had any Win8 devices other than my kid's school latops/tablets .. and I don't like them at all.

My USB3 speeds did take a small hit on the PC .. none that I've yet seen on the tablet or my sons laptop.
It wasn't much, and I'm still playing with various drivers(I rolled back to an older driver which seemed to help a bit). But I'm sure that the USB chip on this motherboard is the issue .. not Win10 as such. It's an old NEC(now Renesas) USB3 chip.
My fastest storage device in the USB3 chain is a Seagate 3Tb barracuda(just a single drive in a no name branded enclosure). It went from an easily sustained 140-ish MB/s over a large(say 500Gig) transfer, to just under 100MB/s with Win10.
While it may sound like an almost 50% difference, when editing files on that USB drive, I never felt any speed difference .. only transferring files .. but I only knew it was slower due to transfer times being a wee bit slower, and testing using various tools.
Now I have it back up to 140-125 MB/s with the latest Renesas driver I had .. but mostly 125MB/s. I think it's heavily dependent on what you're transferring(ie. millions of small files or a few large files).

ps. if you're curious to test storage performance(s) .. try Crystal Disk Mark .. very easy to use and non invasive.