We loved the original 8 oz liners! Then new expandable liners are nearly impossible to put back into the bottles when filled with formula. They get stuck and formula spills all over. We never had any problem with the old 8 oz liners, but the new expandable 10oz liners leak and are very flimsy. Playtex, please go back to your original design! I now have to buy other store brand liners, which are great, unfortunately you've lost a customer.

Really like the "original" version that wasn't preformed and seldom leaked. The new format also doesn't travel well. Buy a different brand or the originals if you can find them. My baby and I have been a victim more than once of a horrendous leak. There's very little lip on the performed and it can dislodge when mixing formula after you put the nipple on the bottle. It has also happen with breast milk - I think I torqued the top too much a broke the seal. We now mix the formula, remove the top, re-seat the container, and replace the top.

I love these liners and bottles! I am surprised it got so many not so good reviews. My baby is 7 months old and after hundereds of bottles later only ONE liner did I ever have leak! AMAZING! Clean -Up is a breeze! No more scrubing bottles everyday! I would use these over and over again without any hesitation! The only con is these are a little pricey but, WELL WORTH IT (unless you love to scrub ba ba's all day!)

These are excellent, but took some getting used to because when I had my daughter, the liners were not preformed. They don't tolerate being thrown by an energetic child well, sometimes. They may come off the ring a bit and leak in that circumstance (which has only happened once).

I use the Playtex Breastmilk Storage system (blue rings and caps) for pumping. With my first child four years ago, it worked like a dream- you attach the pump with the rings and when the liner is full, you put on the sealing ring, turn it upside-down and put it in the freezer. It froze and the liner held its shape, making it very easy to insert in the actual bottle. Now that I have a new baby and am pumping/storing again, I am really frustrated because all Playtex offers beyond the 4 oz drop-ins is the "new and improved" expandable liners or the old-style bags you have to stretch over the top of the bottle (not very convenient). Not only are the new expandable liners less sturdy for handling while pumping and trying to get to the freezer (the old ones were very sturdy and pretty much stood up on their own with the storage system rings/lids on, both on the counter and in the freezer), but the liners are floppy and don't hold their shape and once inverted for freezing, the bags flop over. When I try to put the frozen bag with the storage system into a bottle to send to daycare, the bag is either contorted because it froze flopped over or if I have somehow managed to freeze it upright, the bottom is ballooned out (expanded) and won't fit in the actual bottle. And no, it doesn't work for our family to have to thaw the milk before sending it to daycare. I would like a product that works the way I want it to- I don't want to have to work around it. I find it strange that Playtex still makes the Breastmilk Storage System but apparently hasn't tested it with their "new and improved" liners. I know this product is geared toward formula users, but some people do still nurse and have to pump.

Never had a problem with the old design or these (the new design). They work great, never EVER had a leak. Highly Recommend!

I love the drop in system, it requires less clean up, and when traveling you only need to take multiple nipples and a few drop in bags- real space saver!

These expandable drop-ins leak terribly, no matter how carefully I utilize them. Previously, we used standard 4 oz. drop-ins which worked beautifully. We are very disappointed in this product, and would go as far as saying they seem defective. I will look for generic, perhaps "non-expandable" drop-ins in the future.

These liners make it so much easier to mix up an 8oz bottle. I use powder formula with room temp water. Now that my six month old eats up to 8oz these liners are a must! I've had no issues with leaking, ever. The liners are also recyclable so be sure to rinse out and toss with your other plastic recyclables.

I LOVE the 4oz and the 8oz liners, but these 10oz ones are just a pain. What I like about the Drop-Ins system is that I can look at the side of the bottle, and know how much 6oz is. With these I have to measure out 6oz, then put it in the bottle.