I'm running Windows 10 right now. I had planned to convert my development machine to Windows 10 in the near future but my Windows 8.1 installation actually took a dive on Windows 10 launch day (if I had a tinfoil hat I could postulate a few theories about that coincidence) so I'm running it earlier than expected. So far no issues. It's running all of my games and development software perfectly.
I can confirm the following run fine: Visual Studio 2013, SQL Server 2014, Source Tree, Office, Skype, Spotify, Chrome, Steam, and Crashplan.
EDIT: I just remembered the only hiccup I did have was with the Nvidia drivers. I tried to install the Win10 driver immediately and it failed. I had to let Microsoft install it's generic driver before I could install the Nvidia driver. Kind of weird but in the end didn't cause any issues.