Don’t mind if I chime in with an American’s perspective on this.
We desperately need viable alternatives to the duopoly that is iOS and Android. This is probably more important stateside, because of the literal stranglehold Apple and Alphabet (Google) have in this department. This is why I’m rooting for Jolla to succeed.
Of all the alternate mobile OSes I’ve tried, SailfishOS seems to have the best level of polish on the UI end, followed by Ubuntu Touch. There are still some weird issues I encounter here and there on my Xperia 10 iii with SFOS flashed on it, but by and large, I really enjoy playing around with the operating system and it deserves more attention. I just hope Jolla’s pivot towards automotive OS projects doesn’t kill SFOS for mobile phones.