Canadian here.
I use American spellings wherever they make sense and don't gratuitously mess with the Latin roots.
Such as "behavior", "neighbor".
But: "centre" and not "center" (it's from Latin "centrum": the R goes after the T, and there is no need whatsoever to revise that.)
The shift to Z in the -ise Latin-derived suffix is not just in American English. European languages are split about it. For instance, let's look at "to synthesize"
German: synthetisieren
French: synthétiser
Dutch: syntetisere
But:
Polish: syntetyzować
Hungarian: szintetizálni
Italian: sintetizzare
Romanian: sintetiza
I think the sound is Z in all of them? It's partly a question of whether the orthography of the language uses S for a Z sound or not. If they don't have that feature in their orthography then they don't have the choice of retaining an S spelling with a Z sound.
> (it's from Latin "centrum": the R goes after the T, and there is no need whatsoever to revise that.)
Why does it matter how it was spelled in Latin? English is not Latin.
In the era of ubiquitous access to dictionaries, I'm not sure the benefits of having spelling reflect etymology rather than pronunciation outweigh the cost.
> I think the sound is Z in all of them? It's partly a question of whether the orthography of the language uses S for a Z sound or not.
I'm confused here. What you call "the Z sound" in "synthetisieren" or "synthétiser" does not sound the same as "the Z sound" in "sintetizzare", for instance. The letters Z and S both exist in those languages, but they pronounced differently.