We bought these diapers in the 'regular', which is for babies 15-30 pounds. We were using the Imagine 'smart fit' version before sizing up to these prefolds. I opted for not getting the 'smart fit' again because my baby seemed to outgrow them quicker than the I thought he would.
We used these prefolds with Thirsties Duo size two (which i don't recommend, see my review on those) and with Flip diaper covers with snaps (which I highly recommend and have reviewed, as well). These diapers are a perfect fit with both of those covers.
These diapers are just great. They wash well, they are soft and they hold up really well. We've used them exclusively for one full year (we are just now done with diapers) and they have worn very well. I'm saving them for any potential future children.
I love that they are organic - it was actually harder than I thought to find them. They are a great price, too.
They don't 'quilt' up as much as the smart fit prefolds did, but they are very absorbent. We didn't have any leaks with these.
The only complaint I had is for prefolds in general, they tend to hang on to stains and smells. I had to get some RLR and treat them for ammonia.