I've used them both pretty extensively as well as Red Hat based distros. For me there's a few minor, but important enough to make me stay on pop, differences:
1. It uses systemd-boot as the boot loader. I like not having a grub menu, just turn on my computer and I'm basically on the login screen. It's seamless.
2. Flathub enabled out of the box. I find Flatpaks the best experience for lots of common apps like Slack, Teams, etc. It's a nice feature.
3. Nvidia support in the ISO/out of the box. Nice experience for Nvidia GPU users.
The rest of their stuff, like the windowing features etc, I don't really get much value out of. I like Gnome so I disable most of their stuff.