How’s the quality of the content as compared to Wikipedia’s?

Variable, but generally worse. It's much more tightly censored than Wikipedia: for example, edits are manually reviewed by admins before going live. Also, most community features (talk pages etc) have been removed, so it's constantly gamed to push spam, copy pastes etc and the mods don't really care unless it touches a red line topic like politics.

Can't be worse than Spanish Wikipedia.

What's wrong with Spanish Wikipedia?

I don't know about the Spanish one, but the Croatian one caused a lot of controversy both internally and externally because it was took over by extremely conservative (and sometimes blatantly pro-faschist) group of mods, to the point where a Minister of Education discouraged students of using it as a source.

https://www.dailydot.com/layer8/croatian-wikipedia-fascist-t...

funny to think that, back at college (circa 2003) , when wikipedia was still a relatively new and scary things for academics, we were actively discouraged from using it as a reference for information, let alone a source to cite