Size apart, and small is nice if you want a comapct camera bag, it is worth remembering that even a fast lens can be stopped down to f2.8. And that is where I would normally set my downward (or is it upward?) limit if light isn't a consideration. I like the transition from OOF to in-focus you get at this sort of aperture, not so wide open that things out of focus are a mushy blur, but stopped down enough so there is still some identifiable tonal structure in objects in the OOF regions. It is a classic look, a look where things can encroach into the frame and still be recognisable and not indecipherable, ideal for people pictures, 'street', etc. where a busy image is going to encompass many things.
Steve
Steve