I think that it's much more readable due to familiarity more than anything else. The C syntax for the ternary operator was the one thing that it took me the longest time to get used to when learning to program. I usually just ignored it because it was too hard to remember what it did. That said, I can easily read it now, but I still feel that the Python syntax is more understandable.

Which is more readable:

  > condition ? value1 : value2

or

  > value1 if condition else value2

Maybe the latter is just more readable to me because I'm used to reading Perl all day long that looks like:

  > die unless condition;
  > return true if condition;
  > return false
  >     if condition1 && condition2 && condition3;

That said, I'm also used to reading:

  > return condition1   ? value1
  >        : condition2 ? value2
  >        : condition3 ? value3
  >                     : value4;

and I still find the Python ternary operator more readable:

  > return value1 if condition1 else
  >        value2 if condition2 else
  >        value3 if condition3 else
  >        value4

In this case I think the PEP8 spacing guidelines are counterproductive:

    f() if a==42 else g()

looks much more readable to me than

    f() if a == 42 else g()

You can also write it this way, which is more similar to C:

  x = (a==42) and f() or g()