It works fine for me after the Anniversary Update to Windows 10 Pro (Version 1607). It no longer goes into a coma.
I just traveled all week. Put my Surface Pro 4 (SP4) to sleep 10 to 20 times each day, and currently my task manager shows the up time to be 7:21:35:21 - 7 days! It is actually working the way I expected it to when I bought it!
It was such a relief to not be scared to put it to sleep during meeting breaks to save battery when working with my Pen and OneNote. For the past 7 months I've had to have it on power when in meetings so that it wouldn't go into a coma. That was always so embarrassing.
You can update to the latest version of Windows 10 by opening Settings > Update & security > Windows Update, and selecting Check for updates.