I utilized the N9 for a few months a couple of years ago and just loved the OS. Of course there were bugs, but that's expected from an open source OS. However, the main reason I decided to move on was because of the app ecosystem.
- #1 There's a bug where any text messages received with emoji in them are silently ignored. Not just the emoji part - I don't mind the lack of emoji support - but the whole message.
- #2 Sometimes text messages show up under the wrong person. This is a bug that won't happen for six months and then will suddenly start happening all the time. There are some arcane things you can do to fix it but then eventually it comes back and just gets frustrating. Luckily it's only a visual issue at least and sent messages always go to the right person.
Instead I'm using a Jolla phone which is nice (and has the same alarm clock app design!), although the hardware and software don't work quite so seamlessly as they did with the N9. The curved screen on the N9 worked really well with the swipe system and unfortunately the Jolla's screen is flat.