I bought this to use with my Beco Gemini carrier and am very pleased. It's wide and roomy and yet secures snuggly over my 7-month old. There are two layers--a water-repellant outer layer and a soft fleece inside layer--which I think will be perfect for our Brooklyn winter. Also it has a fully lined hood that tucks away into the cover when you don't need it. (I thought it was hoodless so this was a nice surprise!) Because I wanted an easy-on/easy-off elasticized cover that both my husband and I could use, I also tried out the Baby Bjorn cover. But it was definitely too narrow for the Beco/Ergo type carriers, and my baby's arms stuck out from the sides. The other thing that sold me on the Jolly Jumper cover is that it has two distinct layers (unlike the Bjorn) so I suspect it's going to be warmer.
The only thing that could be improved is the strap that you wear around your neck. It's a basic nylon strap and, unless you're wearing a scarf of high-collared shirt, it tends to rub against the neck. The could have made the strap a bit more comfortable, but I might just sew some soft cotton padding on myself. In any case, a great purchase at a reasonable price.

I really love this keeps my son nice & warm the hood is really small tho & the strap that goes around your neck can be uncomfortable if you wear it without a hooded sweater

We purchased this hoping it would be warm and water resistant while traveling. This product did not disappoint! While traveling in northern Europe during cold, wind, and rain our baby stayed warm & dry. The baby hood that is able to be used when needed (otherwise it is neatly rolled and tucked with velcro out of the way) was great. The hood feature allowed us to cover the baby's head without having to force the baby into a hat while inside the infant carrier. Our baby has a head that is smaller than the hood so when that baby wanted to see out while wearing the hood an adult would hold the extra fabric away from the face. Since the hood was a bit big for our baby, it allowed for "light's out" and successful napping too! Our baby does like to stick her hands up and out of the carrier, so we would use a burp cloth to cover the exposed hands/arms to help keep her warm. We used this product around a soft sided infant carrier while the baby was in the front position on the adult. The elastic around the bottom of the product allowed us to wrap it around the baby's feet when they were sticking outside of the carrier. The baby didn't mind it at all and we were comforted to know the baby was warm. An item to keep in mind is that while the baby is strapped to an adult wearing this product, the adult will also be warm. It seems obvious when I type it, but truthfully I didn't think about it while packing clothes for adults. The strap around the adult's neck is barely noticeable when tucked under the collar or hood. Since we were in Northern Europe, we found the strap tucked under our hoods were the best so that we could access our hoods when needed (otherwise while the baby stayed dry, we would be wet trying to reconfigure the strap to access the adult hood-which is fairly easy since there is a snap for the strap around the adult's neck but easy to manipulate with 2 adults while wearing this product). The adult hand warmer/resting position within this product is great! We kept minimal items inside the pouch for us and I speculate having any additional weight in that pouch would make the strap around the neck more noticeable. We were happy to have a place to put our hands to keep them warm, dry, and to soothe the baby. The clever hand access for the adult to reach into the infant carrier (or to touch the baby) while wearing the product came in quite handy. What a thoughtful design at an affordable price. Thank you!

I love the idea. It keeps my baby warm so she doesn't need a jacket and I can just take it off her when we step into an overheated building. However, like another reviewer mentioned, the strap around your neck is uncomfortable and the fleece isn't the best quality. When I washed it, it shed all over the black part and I have to constantly de-lint the black cover. Overall, I love the idea, the pockets are great too! But I just wish it was of superior quality! This does keep her warm in 40+ degree weather, maybe even too warm considering she is up against my body heat, so we will see how it does in 20-30 degree whether this winter!

When it got to be a chilly fall here, I struggled keeping our baby wrapped in blankets and doing something else, like say, carrying a cup of coffee. Blankets ended up on the ground, coffee got spilled. My heart was sad.
Getting our baby ready for car trips, we had read not to have her snowsuit on her in the carrier, so we were constantly grabbing blankets and hats to keep her mummified enough as we dashed from house to car, then de-mummified her to get her into the seat, strapped in and then piled blankets on top of her.
THEN I DISCOVERED THIS.
We use this in conjunction with our Ergo for super awesome hands-free warmth. It has deluxe pockets - one set of standard pockets and tucked inside those, a slit for hands-on care of your baby. Really nice for readjustments and easy access for extra warmth for your hands!
We also use this for the 15 second commute from house to car. No more rounding up blankets and wrapping her up. This cover keeps her plenty warm and then we pop it over her car seat.
The elastic sides have plenty of room for growing limbs, but work just as well around our 6-month old. Really has been a helpful addition to our winter travels. No one told me about this kind of item and it made a huge difference for ease of traveling with the kiddo.