I am happy to report Windows 10 Preview build 9860 fixes the long-standing USB serial bugs, which impact nearly all Arduino compatible boards.
- The driver loads automatically. No 3rd party INF is required.
- The surprise removal bug is finally fixed (was present in build 9841, is fixed in 9860)
- The seconds-long pause when detecting a new USB device for the very first time appears to be gone.
Windows 10 is finally going to support all class-compliant USB serial (eg, CDC-ACM) as well as Linux and Mac OS-X. Very exciting.