I've been thinking about this since I listened to a podcast today (FLOSS episode 252 where Jono Bacon talks about Ubuntu for mobile phones).
When Android first came out, it was strange and new. Being in South Africa we have excessively high mobile data charges and people were getting slammed by the mobile phone operators for high data usage. At that point the HTC Dream phone was the only phone running Android, I worked as a Customer Service Agent at a mobile phone store selling contract phones. A friend bought one of these phones and managed to install something that totally bricked his phone, he sent it in for repairs and ended up waiting almost 6 months for HTC to send it back. I was NOT going to recommend this phone or the Android brand to clients.
Fast forward 2 years, Samsung had launched plenty of phones running Android (Gingerbread the then current flavour) and the platform had matured a bit. I started to get to know how it works and how to stay out of trouble. Fast forward to today and there are many communities that will help you get the right software tools, advice and ROMs needed to customize your phone.
Why is this relevant? Because we are at the point of Ubuntu phone being launched. It's still a work in progress, but if you listen to FLOSS #252 you will see the passion that these people have for the new platform. Ubuntu One will play a crucial role in everything as you can sync your files across phones and computers, buy and stream music and sync your contacts to it (among other things).
When comparing Ubuntu One to its greatest competitor, Dropbox, you will notice that Dropbox is more polished. Dropbox probably has more money invested in its service than Ubuntu One though.
It's not really fair to evaluate a new platform that's still being built. I mean, the first iPhone could not send MMS messages and iOS 7 has now only caught up with Android as to having live wallpapers. But Android wasn't perfect either when it launched, it's going to take Ubuntu a while to catch up to the competition, and they aren't the only one's trying to get a slice of the action. Nokia and Blackberry and trying desperately to make their platforms a success again, while Firefox OS has beaten Ubuntu phones to market (who knows if they will become a mayor player?).
The future is uncertain, but I wish the Ubuntu phone team every success with their endeavour. I'm not a fan of using Unity on the desktop and I may not like how their phone OS turn out. They have a lot of hard work ahead of them. Google (with Android) proved that it is possible to come out of nowhere with a new phone OS and become a dominant player within 4 years of launching it, so anything is possible.