The ZX was cheaper, easier to pick up programming for, and had a better community around it (probably due to the previous points).

But it was, as you mention, technically much less capable. That said - I never really got the impression the communities were at odds util modern times when it became a thing.

Several people I knew growing up had both for example!

Then again, I was an Atari guy so felt they both were not up to the standard my Atari 800XL set ;)