Nvidia's ShadowPlay and AMD's ReLive are only applicable if you have a graphics card that supports them. They will offer less performance overhead than other options, because they use hardware on the card to do some of the work rather than the CPU, but this comes at the expense of rather fixed settings and a fixed, lesser quality.
XSplit is paid software, but from what I've heard of it from those that use it, it seems very good. I use OBS Studio myself, it's free and works fine for what I do with it.