One of the big problems for the Ubuntu phones was that they weren't available for the US market. That problem has been partially fixed now with the release of the Bq Aquaris Ubuntu phones for everyone.

Up until today, the Bq phones were only available for European users, but Bq decided to make the phone available worldwide. There is an important caveat. The carriers in the US operate on different frequencies, and Bq have been built to work mostly with European carriers. This means that the phones won't have support for 4G in the United States,

In fact, it would be a good idea to make sure that you can even use the phone with your carrier if you live in the US before you purchase it. For now, the best scenario is that you'll be able to use 2G and 3G. LTS (4G) is not supported, at least for now.

This is the reason why I said that problem has been fixed partially. The good news, if you can call it that, is that the Meizu MX4 Ubuntu Edition supports all US frequencies. For now, this particular version of the phone is available only for the Chinese and European markets, but there is no reason to think that they won't open up to the US market as well.

The fact that the phone makers are already expanding to other territories mean that the OS has quite a success, so things have started to move in the right direction already.