I bought iPhone 6 just after it release in 2014. After years it started to be really slow, i got problems with touch on my screen and battery is bad and unreliable. I got good opportunity to get new iPhone X. I don't know if i should get it or pay extra 450$ for XS (or just wait for next model). I want my phone to last minimum next 2 new models of iPhone (2019 and 2020). Will this choice (X) is ok? I know that after iPhone 6 everything newer will be better but if am making choice i want to be sure that I choose best value option.