Maybe my response is not what you want but I will give it a stab. I am currently using a PNS and so is a good friend. My baby wasn't even close to preemie (2 weeks late and over 10 lbs) but hers was... I currently get about 25 ounces of milk per day out of the PNS (while at work); which for us is plenty. I initially started with a Lactina and there was no difference in supply when I switched. my friend's baby could not nurse for about 5 weeks (maybe 6, can't remember exactly).. She was able to pump virtually all of her supply. Our League chapter also had a mom whose baby had cleft palate and she did well. OTOH, with my first I used a Classic, and I got a ton of milk with that.... Just anectodal, but we are pleased with the product. Wendy, LLLL Applicant and MS, MCH Epidemiology