I got to work 40 minutes ago and plugged in my surface, went to windows update and saw the update available, and now my machine is rebooted and logging in to Windows 10. I think that's even quicker than the major OS updates on my MBP.
Yep, I'm pleasantly surprised. Abaqus (a high-end FEA program) is running fine, and CATIA (high-end CAD) works but has some graphics glitches. All of my Adobe CC apps have updated and appear to be working perfectly. I haven't tried Cortana yet but I love the search box next to the start menu button.