I went to the 17 Pro from a 14 Pro. Mainly for USB-C with faster data transfer and the cameras felt like a substantial update (love the 4X and 8X). Features aside, my 14 Pro still ran well (I didn't update it to iOS 26) but the battery life on the 17 Pro felt like double the 14 Pro (not really, but it was immediately noticeable the first week of use that it was holding charge much longer than the 14 Pro). Just battery life alone made the jump to 17 Pro worth it for me even though I really dislike the 17 Pro design, the camera plateau, aluminum vs stainless steel.
I was already having battery issues with my 14 Plus from letting it get too hot that single time and upgrading to IOS 26 made it worse.
It reminded me of what happened to my iPhone 6 when I upgraded to IOS 12. I didn't want to mess with that again.