If you can use ShadowPlay, that is your best bet... though you need to be worry of your setup as well... Shadowplay won't disturb your gameplay so much, but due to its beta nature certain setups (like Asus' GX Mode in Asus soundcards) can cause the recording to fail...
I myself faced with few problems, corrupted recordings, uncontrollable sound volume (probably because I use speakers that time and my mic pick up the audio from speakers, combined with its in-game sound recording, mess up the whole thing), and no-sound in recording due to the GX mode i talked earlier...
but when it works, it works like charms.... a lot better than fraps...