What were you using before ShadowPlay? Know of any good software that does internal audio + video capture at the same time?
I stumbled on this today: Qubicle. Was used by the Crossy Road devs for their art assets. I'm in love. Super-easy to create voxel models.
I was always trying to configure one open-source screen capture solution or another. None of them ever worked particularly well. I used FRAPS a few times in the past, but it always drastically killed performance. ShadowPlay is easily the best video screen-capture program I've ever used. It captures audio from whatever you're running, and even gives you the option of providing microphone narration while you're recording. It's everything I've needed.