I love that I just put it on, snap, and voila! No need to take out inserts. Very absorbant for the first few weeks of life. Looks and fits better than a hybrid shell since the babies are so tiny.
I bought these for my grandson. I can't say anything to function because we haven't used them yet, but I've only heard rave reviews! The appear to be extremely well made. I think they would last through many babies being newborn from 6-12 pounds. Rave reviews, feeling them as well made, and they are really cute, sold me on using these exclusively in the newborn period!
First of all, I am a BIG fan of Grovia! We used their hybrid system with our first son and LOVED them! So naturally, I choose Grovia for our second son's newborn diapers. These worked great until he started peeing more heavily (after about 4 weeks old). I still love how trim they are and the cute colors and patterns, however, I have to keep an eye on them because they will leak if my son has more than one wetting in them. But that is a testament to how absorbent they are because they are fully absorbed when I change him. I plan on using the stay-dry booster with them to get more use out of them.
I have two types of one use diapers, GroVia and Simplex. The Simplex diapers leaked a few times but the GroVia has not. It is very absorbent, soft, and doesn't stain (or at least you cannot see the stains because of the color). The Simplex has much cuter colors but GroVia is a little cheaper and does a better job at containing the mess. I like to use these for the middle-of-the-night changes or for babysitting family members who are unfamiliar with cloth diapers.
Please disregard all the reviews you've read about the old-style Grovia NB AIO (ruffled legs, both cotton and stay dry). The newest style is the only one for sale now. The legs are turned and top-stitched and the whole thing is lined with stay dry fleece. My daughter wore these from a few hours old until ~4mo (14lbs), at which point the absorbency was only sufficient for 1.5hrs. The are super easy to use and beautifully designed. They fit perfectly under NB and 0-3mo clothes while packing in age-appropriate absorbency. This was one of my favorite newborn diapers because it was just so stinkin cute and worked straight out of the dryer -- no tongue or insert to stuff in, no separate cover needed.