On my Surface, I have been on the "Insider" track since the announcement of WSL (aka Ubuntu bash on Windows) at Build 2016. It has made my development work much easier as I can use common Linux or Mac workflows with an integrated file system without hacks like cygwin. However in the small print, I didn't notice you cannot leave the Insider Program at any time.
After realizing that, I stopped trying. But then I dug deeper as the official release loomed. Turns out you just have to wait until the same build from the Insider and standard release are out. Then you can change tracks. So I did that and now I am good on my Surface.
Having used it for so long as a beta, whenever I used my gaming PC which was still on the release version of Windows 10, I missed some new key features. Sure there's Windows Ink and other improvements. But what I missed most was the syncing of notifications via my Android phone and computers via Cortana.
Oh, and the new Skype app actually works!
Long story short, Windows 10 and the Anniversary Update are great. I don't know why you didn't upgrade for free.