If you ignore the massive privacy problems and embrace the Google ecosystem, it's actually quite nice.
Google's ecosystem is a pain in the ass to work around if you don't like it, but I find it two steps above what Samsung is offering, for instance.
AOSP and Lineage are cool projects but their usability still falls behind devices like the Pixel by far. Copying some of the Pixel applications in (possibly after neutering them a little to cover for the privacy implications) can quickly turn a "works, I suppose" custom ROM into a usable experience.
AOSP of course does. Google has abandoned AOSP's to focus on the proprietary Play's ecosystem. Hell, Google has explicitly deprecated AOSP Dialer & Messaging (as has* Music, Calendar, Email), arguably the most essential apps for a smartphone. That said, Fossify (fork of pre-acquisition SMT) provides a very nice active FOSS app ecosystem (only missing a Maps alternative).
*Trivia: AOSP Music & Calendar actually had features removed.