Having been playing with the Pixel 6 Pro since release day when it arrived , I'm in two minds about it and started to go back to my s21 Ultra.
The S21 is better hardware IMO and the finger print scanner is far better along with the mobile 5g reception.
Battery life is very similar, I really wanted to get back to the Native Android experience but now I have it I realise how much customisation Samsung have added to OneUI which make it better in someways compared to the default Pixel launcher.
Silly little things icon arrangement, not being able to turn off the date in the top left and lots of little bugs which can be quite irritating.
I was surprised how fast Samsung launched oneUI 4 with Android 12 actually, they have massively upped their game.
Camera wise it's really close , Samsung has some really great modes such as One shot which has enabled me to take some amazing shots of my kids, Directors view etc . A lot of the time the Samsung can take brilliant pictures, where the Pixel wins out every time is on colour accuracy, I really don't get why Samsung doesn't sort this out. The optical zoom to 10x is very good on the Samsung, I found myself using this more than I thought and even up to 30x then it's a mess.
Going to keep both but it's not a clear win for the Pixel 6 pro, maybe if I hadn't owned the S21 Ultra I would be even more impressed. I'm keen to see how the Pixel improves in software, also shows how close things are at the top of the market.