first , I should say , I be the dude in this happy family , but I have do all the research on this and my wife have be the ` milking cow ' -lrb- she word -rrb- . the pump be relatively easy to use and be effective . it be compact and have enough suction that you will not want to run it a MAX power . the only real complaint for this pump be that it be loud . functionally speak , this unit be as good as Medela 's hospital-grade Symphony . it use all the same plastic cup , tube , valve , and bottle as do the Symphony ; the only difference be in construction of the mechanical pump itself and the interchangeability of the diaphragm -lrb- the plastic ` lung ' that create the suck action -rrb- . we be give use of the Symphony at the hospital , at the time of birth , and as far as we can tell , the pump action be nearly identical to the pump in style -lrb- pi -rrb- . they both use a 2-phase suck action : at first a shallow suck to stimulate milk flow , then after a few minute switch to a deeper sucking to draw the milk . there might be other minor difference in pump action , but no more than the variation expect from person to person . it take about 10-15 minute to pump my wife dry with either of the model . we be tell by the lactation consultant that the Symphony be better than the pi because the `` Symphony be hospital-grade , '' but as far as we can tell , she just assume it must be better since it be ` hospital-grade ' . compare to the pi , I think the factor that make the Symphony a ` hospital grade ' be that the diaphragm be interchangeable -lrb- to minimize cross contamination with multiple user -rrb- , it be waterproof -lrb- so that it can be immerse in water for cleaning -rrb- , it have better environmental seal -lrb- for use in high oxygen , -lrb- i.e. flammable -rrb- environment -rrb- , it be very durable and it be quite . while all of these be nice feature , it do not change the effectiveness of the pump . I think the Medela PIS be a smartly design and nice styling , and if you plan on carry it around with you , the pi be a excellent option . it be not super compact , but the penalty to portability have more to do with all plastic hardware -lrb- cup , funnel , etc -rrb- and less to do with the pump . the pi even come with a option to operate the pump with a set of aa battery -lrb- which we have not test -rrb- . unfortunately , the pi be loud -lrb- reasonably so for a portable , consumer-grade pump but loud none the less -rrb- , which mean that if you go to pump at work , everyone will know exactly what you be do and when you be do it , even behind closed door . if that bother you , you can buy the Medela 's Freestyle pump which be suppose to be quieter , but I think a better , cost-effective solution might be to simply rent the Symphony ` hospital grade ' pump . I wish we know about this before we buy the pi , but many hospital will let you rent a Symphony pump for $ 40-60 per month . in the end , the total cost for rent the pump over 5-6 month will be the same as buy the pi , but the Symphony be so much quieter . of course , you will have to buy the plastic hardware -lrb- cup , funnel , etc -rrb- for about $ 40 , but if you be lucky like we , you birth hospital use the Symphony and will give you a set of plastic to use during you stay there and take home when you leave -lrb- just make sure to take all of the part , include the tubing and diaphragm -rrb- . the Symphony be somewhat portable , but if you plan on leave the pump at a remote location -lrb- like work -rrb- , it seem to I like the best solution . and in term get more value out of the pi over multiple baby , we have only use it for a few week now , but to I , the pi do not seem rugged enough to last more than 7-8 month , which mean you many have to buy one for each child . another point about the pi , if you choose to buy one , we have read that you should not share or use a use breastpump , due to risk of cross contamination . evaporation from the warm , pump milk will inevitably get suck into the tubing and down to the diaphragm ; the trap moisture could lead to growth of mold and mildew . this be why the FDA classify the Medela pi as a ` personal use pump , ' and the Medela 's Symphony , with its interchangeable -lrb- i.e. disposable -rrb- diaphragm , as a ` hospital-grade ' . but with the pi pump , you can remove the face plate -lrb- it be design to snap on and off by hand -rrb- and get easy access to the diaphragm . while the diaphragm itself be not removable , it can be clean with soap\/water and disinfect with alcohol . indeed , even if you buy it brand new , you should not assume the pump\/diaphragm be sterile out of the box , and you may want to clean and sterilize it before first use -lrb- and every once in a while -rrb- . this apply to the nylon sack and tote bag . with the pi , just about the only thing that be difficult to clean and sterilize be the nylon tubing , but you can purchase a new set for $ 10 .