Are pretty claw hammers better? By pretty, right now I'm thinking of
the ones with corners on the shank just below the hammer head. Does
that shape mean they are made with a different, better method?

Or maybe they are made with a cheaper method but made with corners to
imitate better ones?

Or is the shape just a style and nothing more?

There are also hammers with 8 sided heads, rather than circular. For
some strange reason I can't put my finger on, I don't like them.
That's just a style, right?

I've never broken a hammer, even one that I'm sure was cheap. But I
have had one or two where there was something wrong with the V between
the claws and they didn't grip nails with small heads well.