My first OnePlus was 12R when it came out. Used it till last month when I got 15 because work was paying for it. In terms of performance, I dont see a difference, guess flagships have matured. However the 15 is a beat when it comes to battery life. I literally get 2-3 days of battery life. Never worry about battery life when going out or at anytime. Pkus it's the flagship Snapdragon soc so it runs anything. Money well spent. Too sad that they are closing shop