I bought a Meizu MX4 Ubuntu Phone in 2015 for €300. This was quite early on in the development of Ubuntu Touch, and overall it was pretty good.
The operating system was pretty solid, and I really liked the lock screen design and pull-out Unity sidebar. It was fast and sleek, but didn't quite yet have the polish of something like iOS - which of course is to be expected for something early in development.
As usual with less well-known mobile operating systems, there were very few apps available. You could get many of the hacker-y/privacy ones that us HN lot probably use, but if you wanted a 'mainstream' social app then you probably couldn't.
After a few months I did end up flashing Android onto the phone, mainly because of the early Ubuntu Touch versions lacking features.
Hardware wise, I still have the handset today and it's great - performance wise the phone was ahead of its time when it was released in 2014, and it still performs well.