Most reviews are from folks who had it for a few hours and then go back to their usual feature-full system.
I did an honest effort though. It's not even about the apps. I could manage without them. The problem is Ubuntu phone was utterly broken. Slow as hell. Everything browser based, but they provided the worst browser (it couldn't even parse css for some sites). The team behind was like 10-15 people. You cannot pull this show with such a small team. The phone email app was left to the community. They have only recently figured out how to provide email notifications (this is the extent of brokenness - a mobile OS which cannot notify you of new emails...). There were problems with the calendar, the Wi-Fi, the contacts sync.. The gesture system was awesome. but the UI was laggy, buggy. The idea of scopes was nice, but they were broken: the news scope didn't pull the news, the one showing the weather didn't show the weather etc. to the point I just left the app list.
And the worst was the lock screen. No pattern unlock. instead a circle which would show a text in the middle informing you of how many pictures you've taken or how many messages you've sent. But no way for it to provide actual notifications!
This was an OS that was live, commercially sold, and in reality it looked like a pre-alpha build of a proof of concept.
I am sure some things have improved (cannot get worse), but Canonical has clearly not the muscle to take this idea anywhere and is of course leveraging on community to do their job while milking whatever profits from the few adventurers who pay for it. I wouldn't be surprised if they dropped the project entirely at some point. I'll be sorry for the people which have contributed apps to this ecosystem. Ubuntu phone pretty much killed the reputation that Canonical had left for me.