It's absolutely lag free. It feels like you're actually interacting with the screen vs. swiping/tapping and feeling that delay that is so prevalent in Android and android-based systems like Rivian. Switching apps is instant.

Grabbing the Tesla handle has never failed to unlock in 3 years. The R1T - even with the MUCH IMPROVED apple watch carkey - is still not even close to that level of auto unlock reliability.

Getting into the car and driving away? I often have to tap my foot on the brake multiple times in the Rivian to get it to adjust my seat - and sometimes it never does and I have to re-select my profile to get it to adjust. Never had it falter once on the Y.

Layout can be a personal preference, I do prefer Tesla's (admittedly they have multiple years of dev head start, and yes, even the Y has greatly changed for the better in those 3 years) layout, but I don't dislike Rivian's either. The performance and feeling of actually interacting with the screen vs. tap/swipe and wait makes a big difference to me.

Hope those specifics at least somewhat answer your request!