I have had a PISA and a regular PIS now... I prefer the regular PIS. More control over it myself. The let-down phase is kind of silly, every woman has a let down in a different amount of time... I get a let down very quickly, and would still be in let down phase and then my best friend, let down phase would finish and she didn't have a let down yet. I think the advanced is a waste of money, just my opinion though.