OnePlus launched a new OnePlus 6 on 16 May 2018 in London event.
Official IP rating for water resistance is marked to S9 while OnePlus 6 has no official IP rating, only there is an improvement in water resistance as compared to OnePlus 5.
OnePlus 6 vs Samsung Galaxy S9: Display
Samsung Galaxy S9 offers 5.8 inches and S9+ offers a 6.2-inch display with the same resolution of 1440 x 2960 pixels.
OnePlus 6 has a notched display with 19:9 aspect, slightly taller than the S9 (18.5:9 aspect).
When it comes to protection, both devices contain Corning Gorilla Glass 5 and Samsung S9 with some extra features such as HDR10 compliant and 3D Touch (home button only).
Do you want to buy one of these phone.Don't forget to sell mobile phone if you upgrade to a new phone.