It appears as though just installing the APK doesn't get you all of the Google Voice integration -- you need to wait for some server-side changes to your account as well. (Discovered this after a frustrating hour or so of trying to get GV features to work...)
I'm not running stock, CyanogenMod 10.1.
That said it successfully called my desk phone, and I could successfully call hangouts, but after both the app crashed, and every subsequent launch after that.