I had been using win10 preview on a laptop, and was intentionally NOT upgrading my SP3 due to my concerns about "tablet mode" functionality, compared with ver 8.1. But after accustoming myself to the new OS, I realized that everything I did in 8.1 could be replicated, with just a slightly different swipe here or there. So I took the plunge. My SP3 is now running Win10, and I really don't miss anything! My advice to anyone who is still on the fence, wondering if to upgrade: go for it!