For my occasional video recording in-game, I had been using Fraps for quite a while (the... um... paid version <cough>) so that you have the buffer.
I thought I'd try the other options mentioned in this thread. For what it's worth, here are my 2 cents worth.
TorTorden wrote:And not that i have had much problems, if shadowplay crashes it has a much greater chance of taking the driver and any game you are playing with it.
I have a GeForce GTX 970 in my i7 4770 Win 10 64 bit system, so I tried Shadowplay. The first session generated exactly what TorTorden mentioned. I got an error while in a crime sweep with another commander. Shadowplay and GE Experience crashed and took E-D with them. Not cool.... not cool at all. I've never had that issue with Fraps.
Turned off shadowplay and setup OpenBroadcast. I setup the most simple hotkeys that I could think of, but it still took a few button presses to get the buffer going, then a button to record from buffer, then another one to stop recording, and one to stop the buffer. Sheesh... that's a lot for an old guy to remember! It ran fine, but no noticeable benefit over Fraps and I didn't see a way to stay in-game and be sure that OBS was doing what I wanted it to be doing.
So.... yup... I'm back to using Fraps. It works well for what I need, which is just to record a buffer and continue recording in-game when something cool (or something very not-cool) happens.
Oh... and I control it with just one hotkey. If it's in standby, hitting F9 will start recording. Hit it again to stop. Want a buffer to start running? Just hold down F9 for a couple of seconds, and the buffer starts (visual verification in game by a color change of the FPS counter). Want to record the buffer and keep recording for a bit? Yup... you guessed it...tap the F9 key (another color change verification via the counter). Want to end the recording now? F9. Simple as hell.... just the way I like it.