On mobile, I have been playing Stadia with my Xbox one controller (because I had a mount) with bluetooth.
The lag... Lag? No lag, I still can not understand how... It is just instantaneous.
So I was thinking about buying the Stadia phone clip but tried the controller plugged on my phone... Oh buy, why? I immediately noticed a lag... I unplugged it and used the Xbox one controller with bluetooth and 0 lag...
So 2 question :
So I'm waiting for my stadia controller, which arrives on Tuesday; however, I'm currently playing stadia games on my note 8 and laptop with my ps4 controller. On my note 8, I notice input lag playing Grid (I haven't tried other games on the phone); on my laptop, there is zero input lag playing any of the games I've played, including Grid, Division 2 and the latest Serious Sam, which is an insane FPS game. I'll update how playing on the phone changes with the stadia controller.
I returned my complete Stadia bundle with my extra controller because my experience playing with the Stadia controller was so poor.
imagine my surprise when today I tried stadia on my Laptop with my Xbox One controller (Bluetooth) and everything worked perfectly adequate.
You're not alone OP.
UPDATE: I received my stadia controller over a week ago; I've been primarily playing on my 65" 4k tv, laptop and less on note 8 (because I don't have the support claw) and I've experienced no input lag playing Grid using the cable.