1. Spam call screening is nonexistent on the iPhone, and T-Mobile's blocker still lets a ton of them through. In my prior experience Google did a much better job in this department. It would be nice to pick up the phone without a 90% chance of an annoying spam call.
2. Speech to text on iPhone makes a lot of mistakes and Google's latest update looks like they've widened the gap even more. I don't want to handle my phone to text while driving, and when the interpretation is wrong it requires extra keystrokes to try again, correct it, or type the message if urgent. This is unsafe.
3. I find FaceID annoying, and after replacing the iPhone screen because I cracked it, FaceID got noticeably worse. With a fingerprint I can have the phone unlocked before I even pull it out of my pocket, especially these days when we have masks on.
Plenty of other sexy features like camera and the customer service line feature are very nice to have, but in my opinion these are major benefits in terms of everyday usability. The overall integration across services is just smoother too, in terms of flows like email -> calendar -> google maps live traffic, or email -> boarding pass QR code. I am and will always be a PC user so I don't benefit from those integrations with Apple products.
Making the switch will require ditching Airpods and the Apple Watch, but I think it might be worth it for me.