6.1" iPhone will be the best variant of 2018 as long as it retains having the A12 chip, same cameras, and has same amount of RAM as the X2 Plus.
Metal > Glass
LCD > OLED
I don't care about wireless charging and OLED is overrated with a shorter lifespan than LCD. Apple didn't even utilize OLED to begin with like no Moto X Active Display or always on display.
Apple should call this 6.1" model the iPhone 9 because it's different enough from the 8 but similar to the X design with only the cheaper LCD and will lack wireless charging. The other two could be called X2 or Xs/10s.
It helps that it will be the cheapest of the trio. Why would I want another glass back phone that is expensive to repair? Glass is weaker than plastic. I don't use wireless charging. I have used OLED displays and it's overrated as curved displays. Don't fall for the Samsung propaganda.
iPhone 9
iPhone Xs
iPhone Xs Plus
The 9 is the winner to me. Best value that lacks overrated features like OLED and glass backs for wireless charging .