Google Hangouts is basically the same as FaceTime. But I use HD Voice / Video calling. I think it's carrier-dependent...I have Verizon and I make video calls to my family all the time, straight from the normal phone app. There's a regular phone icon for voice calls, or a video camera icon to make a video call. You can even switch from one to the other mid-call. Works awesome, integration is perfect. You have to enable it from the settings menu, I think it's under Advanced Calling.
I haven't tried to do video calls to friends on other carriers yet. Plus it's only for Android. You would think that all the carriers would agree on one VoLTE standard so we could all video call each other.