-few cli linux tools

Um. There's a lot available - even in the official repos - that doesn't show up in jolla store. And more in Openrepos.
Ever tried some 'pkcon' commands in the terminal / via ssh?

-more closed than N900 = harder to fiddle/hack/program

Unless you have specific examples, this is either highly subjective or simply not true.

-no raw pictures

Maybe Advanced Camera can? I'm not sure. Maybe not.

-no arrows/ctrl keys to select/move into text

Well, it doesn't have a physical keyboard obviously but virtual keyboard extensions for that exist, I'm using this.
Text selection is tricky though, no argument from me.

-some closed parts, no guarantee I am not spied

Isn't N900 partly closed too, if that's what you're comparing to?
Also, did you ever read the license, TOS & privacy policy for SFOS?

You might want to check out the SFOS articles in my signature.