Given that they have exactly the same interface, that choice is really easy. You go with one until it turns out to be insufficient, and then you switch to the o

Given that they have exactly the same interface, that choice is really easy. You go with one until it turns out to be insufficient, and then you switch to the other and not a single line of code has to change, except at the point where you create the thing. Incidentally, the same is true in many situations in Python, and that is (IMO) one of its strengths.