I like those, but they do need to be properly formatted and only "tail-nested".

I also tend to format them thus:

    int a = b == 1 ? 2
          : b == 2 ? 3
          : b == 3 ? 5
          : -1;

Feels much more "case analysis-y" and clearer.

Still, a language having proper support for expressive conditionals is probably better.

Also the way Python's ternary was defined means it should never ever be nested, it looks nasty.