I can confirm that the PPA will still work if you manually change the distribution back to vivid after upgrading. (3rd-party repositories are disabled after upgrading anyway, so there won't be any immediate problem)
However, OBS no longer records properly on Ubuntu 15.10. Any recording attempt crashes the program with the message "Couldn't initialize muxer"
The following packages have unmet dependencies.
obs-studio : Depends: libx264-142 but it is not installable
E: Unable to correct problems, you have held broken packages.
afaik you can't (At least on Xubuntu 15.10)
Maybe you have an old libx264-142 installed, which isn't available any more in wily?
For Wily (15.10) it's libx264-146 version.
In my case, I'm forced to stream from windows, pending the wily version.