Interesting. I made the same jump and noticed a huge increase in speed and decrease in memory pressure (the likelihood that iOS will kill an app I've switched away from). I miss the physical silent mode button though.

The new button was driving me a little crazy I hit it now and then when I think I'm doing volume up. I wish they had moved that button literally anywhere else.

I honestly never noticed memory pressure. I am not a heavy app user. Chat, browsing, and pictures of my kids are the vast majority of my phone usage. Not exactly intensive stuff.

The camera button on the 16 seems to have been perfectly engineered to be exactly where I grab my phone. I'm sure I'll get used to it, but in the mean time I have so many blurry photos of desktops and pants to enjoy.