My 930 is on the latest 10586.63 build, and is working very nice!
BUT:
The windows camera app in W10 makes less quality low light pictures as the lumia camera app does in 8.1
And shooting a movie does not record sound!
There might be some apps you have now in W8.1, which are not (yet) compatible in W10, so take notice of that.
And sometimes the user interface is a mix between W10, and W8.1....
For the rest, W10 has a lot more to offer then W8.1 had, and it will only get better!