I've had my new IQ Duo for 2 weeks now. Previously, I was using an Ameda PY, which I used several years ago for my daughter and began using again for my now 4 month old son. I work full time, so use the pump 3 times a day during the week. I bought the new pump because the motor on my PY was getting a little flaky and I was hoping to get more milk with the Duo since I'd had good results in the past with the Isis manual. It does seem to help me get more milk - at a good pump, 6 ounces instead of my usual 3 to 4. So I'm extremely happy with the pump in that respect because right now, my life is all about having enough milk to leave for the next day. I thought I'd elaborate though, so here are my pros, cons, etc...
Pros:
You can adjust the suction strength, length of time the suction lasts, and the "rest period," all just by pumping manually a few times. This is the exact reason that I splurged on a new pump. With the Isis manual, I would always hold the suction until the milk stopped spurting. The cycle settings on my PY went nowhere near holding suction for that long. And when I made the cycle longer on the PY, the rest time between suctions seemed to increase too. With the Duo, you can make the suction period really long and the rest period really short - or any other combination that works for you. I can almost always get a second let-down, which was very elusive with the PY.
The cord is very long and the plug is a standard plug, not the big boxy thing like on the PY, so it takes up less space on the outlet.
I like the bags they give you for carrying your horn setup. And I like the fact that you can, in effect, seal off the horn assembly with the sealing base and the cover/bottle holder. It makes it very convenient to store them in the fridge in between pumpings (which of course the manual says you're not supposed to do since they should be sterilized before every use).
Supposedly, the valves don't need to be replaced for a very long time. The customer service rep I spoke to said with proper care, the valves would last over a year. And they include 2 extra valves in the box.
Avent customer service is great. I called to order extra horns ($9 each) and diaphragms ($15 each - maybe that should go in the cons), and the lady had a long conversation with me about how I liked the pump and offered lots of tips.
Cons:
It takes a lot longer to set up than my PY. With the PY, I always left the tubing and power cord attached. The Duo needs to be unhooked to fit in the bag. I did finally figure out that I could leave the power cord plugged into the pump and still zip up the front of the bag. I suppose I could do it with the tubing and control wire too, but I'm afraid they'll get bent or crimped so I unplug them every time. There are also a lot of things to connect - the air tubing, (which is a pain to plug/unplug because you really have to yank on it) the control wire, and the electric cord, which comes apart into 2 pieces, so I know one of these days, I'll be missing one piece of the cord and have to run home for it.
Once you've got the horns attached to the bottle, the setup doesn't stand up by itself. I think it's the petal insert that makes it top heavy. They do provide the piece that seals off the opening of the horn and doubles as a stand, but for me, it's just one more piece to forget. And if you're using the VIA bases, you're out of luck since they don't lock into the base stand. The control handle takes a lot of force to pull off- I'm afraid I'm going to be pulling too hard, have it pop off, and then knock over my bottles.The tubing is also fused together about half of its length (from where it connects to the pump up toward the control handle and double pump cap), which makes it very precarious to detach the tubing while holding both bottles so nothing tips. Also, the tubing (with the integrated control wire) is very heavy and stiff, so handling everything is awkward and it seems like there's more chance for accidentally knocking, dropping, or tipping. And yes, I do cry over spilt milk.
The cooler bags are small and have no handles for carrying separately. And who wants to keep track of 8 little icepacks? I already lost one somewhere in the depths of my freezer. Each bag only fits 2 4-ounce bottles or 2 6-ounce VIA bases. And the VIA bases especially are a really tight squeeze to get in there with the 4 icepacks.
The motor really doesn't seem any quieter than the PY, which doesn't really bother me except that the advertising led me to believe it would be quieter, and I can imagine it might be important for some people.
The control button is in a bad spot for anyone who sits at a desk while pumping. I keep hitting it on the edge of my desk, which makes the motor stop. I do like the fact that they put the control on the handle within easy reach, I just think it would have been better placed on the top somewhere. It also seems to be a little harder to lean against the edge of my desk to hold the horns on and continue to type with both hands like I do with my PY. I think the petal inserts make it not suction to the outer part of the breast as much, so they're harder to keep in place just by leaning against something.
Lack of "custom" parts. I started using the larger barrel diameter horns with my PY, and Avent doesn't offer (and has no plans to offer) a larger diameter horn. Without the petal insert, my nipple eventually gets sucked all the way to the back of the barrel. I have to keep breaking the suction and reapplying. With the petal insert, my nipple doesn't get sucked in so far, but I still have milk ducts that are up against the side of the barrel (which also happens with the standard PY horns, and didn't seem to affect my milk production too much).
The Duo seems a little less comfortable to use than my PY. I tried both with and without the petal inserts, but I seem to get sore no matter what, whereas I don't with the PY. Or maybe I have the suction stronger- I will have to experiment with that.
Milk gets stuck under the diaphragm part, so when I'm done, I need to remove that part and dump that milk into the bottle. It just makes the whole process take a little longer.
Versus the PY, there are a lot more parts. The integrated air tube/control wire and the control handle are probably expensive to replace if they break. They look pretty durable, but being external parts they'll be exposed to more wear and tear. Avent customer service couldn't even give me a price for replacement of those parts, but did suggest that they would work with a customer if there were any problems.
Nit-picky things:
The status light is not visible when the pump is in the bag, so if you want to leave it in the bag while you pump, you need to pull it out a little to see it. You're supposed to check that the light goes from flashing to constant on before starting, which happens within seconds, so it's not that big of a deal.
It would be more convenient if the zipper on the front where the pump is stored were a 2-zipper system so you could pull both zippers up from the sides toward the top.
Observations:
I always get more milk from the non-control side, even though I've tried the control on both sides. The Avent rep said suction should be equal on both sides and suggested that I check and make sure everything was sealed correctly, which I've done but still seem to have a problem.
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Philips Avent Isis iQ Duo Twin Electronic Breast PumpProduct Description: Avent Isis iQ Duo Breast Pump The Avent Isis iQ Duo Breast Pump is the first breast pump with an iQ.The Avent Isis iQ Duo features an electronic memory that learns from mom!It is by far the most personal Avent breast pump and, for that matter, the most personal breast pump period!It is the only breast pump designed to respond to the needs of a breastfeeding mother. The Avent Isis IQ Duo is a high performance electronic pump which combines all the features which improve milk production.They are features like natural let down, efficient double pumping and infinitely variable control for precise comfort.
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I have found these bags to be the best ones out there. They are thicker mm of plastic, have a double seal and a separate area to write on to avoid ink contamination. In my opinion, they are also much easier to pour to/from than other brands. 
