I OWN a Note 7 and so does my brother and his lady. No reports of lag. Is it as zippy as an iPhone 7? No. Then again, iPhone 7 isn't running at 1440p and has half the features of a Note. Perhaps that Youtuber had a defective Note 7? The new v2 Note 7's with the newest update is faster and more responsive.
I had Note 7 and returned due to the fire situation. After so many years with iPhones I feel a bit uncomfortable with Samsung, but I must admit it was almost as fast as my buzzing/defective iPhone 7+. I tried Galaxy S6 before and didn't like it. Note 7 is a huge step forward.
I'm an Apple guy, but I like Note 7 the same way I can like flawless iPhone 7