I bought an Aquaris M10 Ubuntu edition long ago, and upgraded it to UBPorts when Jan Sprinz (I think ?) and his team came to the Ubucon.
I haven't used it much anyway, one of the reason being that under UbuntuTouch it required a UbuntuOne account to install anything (and yes UbuntuOne accounts were deprecated but it still required one).
I fired it up a few weeks ago and found that the OpenStore had only a blank page, so I can't install any application.
And this even after I updated the OS to the latest UBPorts version.
I'd rather use apt-get since I bought a Ubuntu edition tablet in order to have a Linux tablet, but everybody told me that I shouldn't do it and use the store instead.
But if the store is unusable it means that the tablet is now of very limited use, especially since the default web browser is awful (no adblock or NoScript equivalent, for instance).
So is there a solution to fix that ?