They are a great all day diaper. I think the plastic feels the same as the rearz mermaids. It's slightly transparent though, so you can see what you are putting in there. As for the fit and capacity, it's about the same as the rearz mega diapers. The 11 litre capacity they claim, I'm assuming, is in a lab environment with pure water. So your results will vary.
I like them and have already gone through two packs since they launched