Right now, I have a OnePlus phone. Though for my next, I may buy a Pixel 3 for it's Titan M security chip.
The Titan M security chip is an isolated processor and memory. Google took their Titan Chip in their data centers and modified it for mobile use.
The first level of security seen comes from the bootloader. The chip is integrated into Verified Boot, Android's way of authenticating each stage of the boot process. Titan M can protect against bad actors trying to guess your passcode hundreds of thousands of times per second by limiting the amount of attempts. Also, all content on the device is encrypted, and can only be decrypted when the correct passcode is input (shouldn't this be standard?) through the chip's verification. The firmware cannot be tampered with unless you know the passcode.
It allows apps that store sensitize information, such as e-voting, money transfers, sensitive communications, etc., to keep their data in the chip as well as generating and storing private keys. This is also the first iteration of Android's Protected Confirmation, faciliated by Titan M, which requires user verification to prevent bad actor attempts in sensitive apps or transactions.
For security-conscious people, this sounds compelling. For the not so security-conscious, this is behind-the-scenes security that you will love.
I don't demand much from my phone, but by god do I want the data onboard to be my eyes only, under all circumstances. The cheapest phone with Titan M is $400, the 3a. Maybe once my OnePlus phone bites the dust.