There is nothing wrong with mixing tabs and spaces. It works great.

Provided everyone use the same tab width :)

Nope, works regardless of tabwidth; that's the point. Tabs for indent (these change size with tabwidth), spaces for alignment (these don't change so things stay aligned).

Oh, you're right. I should have tried it before commenting :)

Until Python. Then it doesn't.

tabs for indent, spaces for alignment works great with Python.

What's a compromise about it? Alignment and indentation are different semantic things, so it makes perfect sense to mix them.