thumbs up!

Congrats on your first article!

Hmm... You say that no other mobile OS offers a developer mode.
I would disagree a bit. It is possible on Android: Sony (and SE) allows you to unlock your bootloader, which gives you complete access to flashing your device and getting all kinds of root without having to do any special tricks ( http://unlockbootloader.sonymobile.com/ ); and as far as I know, the Nexus line from Google gives you the same kind of access.
But not ALL Android phones give you this, especially operator sold ones (for instance, Sony/SE allows operators to disable the bootloader unlock option).

But yeah, I think Jolla is doing pretty good in this department too, although I do wonder about the security of the current developer mode --- if I steal your Jolla, can I enable developer mode and use root to get all your data?

I spotted a few typos too:
ment => meant
Salefish => Sailfish

Keep up the good work :)