I've never tried either one, but as a user of essential oils for over ten years (and certified in aromatherapy), I would stay far away from Young Living essential oils. Young is a businessman and a con-man, but not an expert in essential oils. There is much information about his past online, you just need to do a google search. Personally, I wouldn't trust anything with his name on it. The "quality" of his essential oils seems to be nothing but hype. I've yet to hear a YL follower speak anything but nonsense when it comes to essential oil quality, use and safety. I can't outright say YL oils are bad, but you couldn't pay me to use them, just based on this man's past.
Although I've never tried doTerra, out of the two, I'd try that one.