Right. I have the basic one (PIS) and the pump appears to be the same besides the extra features of the PISA which has the 'let-down' features (pumps faster when you turn it on to be more like baby's sucking pattern but you can turn yours up fast and then slower if you have the PIS). The freestyle is a lot smaller so I'm not sure about that one's pump but from what I can tell no one seems to pump 'better' than the other. It is hard to say for sure b/c I haven't (and probably have very few people) 'tested' them all out to compare.
I'm not sure if they have different suction or not, but I've been very happy with the suction of the freestyle. It's tiny and lightweight (which is what I love about it since I use it at work), and it seems to be really powerful! Maybe not quite as powerful as the pump I used at the hospital, but pretty comparable.
I love being able to use the pump on its battery, which I don't "think" the other models have.
It's been my "must have" item and I've used it constantly since I've been home from the hospital.
Re: re: medela breast pump post below
I'm not sure if they have different suction or not, but I've been very happy with the suction of the freestyle. It's tiny and lightweight (which is what I love about it since I use it at work), and it seems to be really powerful! Maybe not quite as powerful as the pump I used at the hospital, but pretty comparable.
I love being able to use the pump on its battery, which I don't "think" the other models have.
It's been my "must have" item and I've used it constantly since I've been home from the hospital.
Maybe call Medela and ask? They should be able to tell you what the 'power' of each of these double pumps are in comparison to each other.