The Surface Pro 3 pen works with Windows 10 Technical Preview Build 9879. Many testers worldwide continue to report pen inking probems, though. I was one of them. Solved here: http://www.surfaceforums.net/threads/windows-10-on-surface-pro-3.11828/page-31#post-99567
While I'm sitting here rebuilding some laptops I noticed that my desktop computer that I installed the Windows 10 Preview just decided to reboot. After awhile I discovered that it was now at build 9879. I guess they just like to surprise people. I than went to my Surface 3 an found that a new build was ready to install so I'm in the process of letting it do it's thing. I wonder if there is any write up that tells what has changed from 9860 to 9879. I wonder if that just got released this morning? I hadn't seen any posts here about anyone else getting it.
Go here, bluegrass: http://www.surfaceforums.net/threads/windows-10-on-surface-pro-3.11828/ By the way, you can keep up with new Surface Forums postings by clicking "Active Topics" at the top of the site page.
Thanks Sharp. Will keep that in mind. I've been scanning through threads for ones that have today on them.