Earlier quoted context omitted.
I was under the impression that using a class (with `__slots__` set) or a tuple is generally more performant than using dictionaries. At least, I assume that's why he didn't mention dictionaries.
The attributes of an object (and its class) are generally stored in a literal dictionary, so it's unlikely that a class will be more performant. What a class buys you is behavior and a semi-defined interface.
[1] - http://stackoverflow.com/questions/472000/python-slots