I went from 6 to the 8+ in Sept AND the X in mid Nov last year and the speed was like night and day. Battery life much improved as expected between an old 6 and a new 8+/X
I did return the X in early Jan. - Selling the 8+, I would take a big loss of money even on a 7 week mint condition phone, But "test driving" the X was nice...but I simply liked a larger phone. I read the early rumors of a X Plus, larger X, so I figured I'd return for the full refund, keep the 8+ wait for the X Plus - and it looks like that is happening (prepare to take more of my $$$ Apple 🙄 )
(XS, X Plus...whatever it will be called) coming out, it will even be faster. The upgrade will feel absolutely amazing for you. Personally I liked the slight learning curve for the new X last year, As for the "notch" --- yeah I HATED IT when I first saw the design as did many others, but seriously after using it in the first few hours, I forgot it was even there. Thats just me