01/24/2019 (Thu) 09:47:00
It isn't really open source actually (it is Jolla, not N9 from Nokia). There are closed parts, including some apps and part of UI, but it doesn't matter anyway. For example, browser is open source, yet no one still really did any code, except Jolla devs.
As phone it was pretty usable, I've used it daily. It has android compar layer, so many apps work (many don't though, because it is 4.1). Native apps are ok, but there aren't many of them, and some of them suck (like native default email and jabber clients).
Companies and services of course wouldn't make own apps for small unknown platform. GUI is pretty and usable, it is very swipe-centered, overall OS is pretty fast on slow hardware (faster than android of course). Apps are made with Qt (C++ or Python) + QML. Internals are plain linux, i.e. rpm, systemd, wayland, just average modern linux distro. Few features I've missing at android now (bought some cheap chinese thing for emergency reasons), although technically android is much more polished and usable for average user.
Sadly, internal partition died on upgrade, looks like it is just age, device isn't even could be flashed anymore.