First, Always On Display (AOD) was there initially, but the day one system update removed it, leaving only the option to have the screen wake up when you pick up the phone or a notification arrives, I wonder why remove a feature on day 1....
There is no way to show battery percentage in the status bar.
Navigation bar is always white even when using a dark / black app, looks really bad.
A lot of settings have been moved around, and generally the settings app does not feel like stock, the Razer phone managed to add extra options while still feeling and looking stock like, I would not call Oxygen OS stock like.
Adaptive brightness is all over the place and feels like a beta product.
I really really wish it had wireless charging.
I will keep this post updated as I find more things worth noting.
On the positive side.
Fingerprint and face unlock are incredibly fast.
Phone feels really smooth and fast.
I really like they include the advanced reboot option in dev settings.
Camera looks really promising, tho I only tested so much for now.
Let me know if you have any questions.