Today is the day when I gave up on the Ubuntu Phone. I sticked with it from May until the end of the year, updated it whenever there was a new update, but there was no significant improvement.
The main reason I quit for now is the lack of push notifications. I use my phone for communication, like probably most phone users. By sticking with the Ubuntu phone was like not having a smart phone at all. Only Gmail notifications worked, but I usually do the messaging on Facebook.
Another interestig problem was with the mobile internet connection.
I use a very limited connection for most of the time, because it is very cheap, and on an android phone I was able to stream a low bandwith internet radio with it, which is pretty much enough for me for the price. However this did not work on the Ubuntu Phone. When using this limited connection even the Gmail WebApp did not come through. (However gmail loaded through the browser, very-very slowly).
Lucky me, there is a way to convert the phone to Android, and this way at least the hardware is not wasted.
This is the tutorial: http://a25.co/ubuntu-phone-how-to-install-android/#fnref:1