GroVia Organic Cotton One Size Diaper
I love the Grovia system! I have several shells with inserts, the inserts are great because they snap in place and do not move around. I really like this AIO as well, it fits my slim twin babies so perfectly! No leaks so far, but my babies are only 9 weeks old and are not what one would consider "heavy wetters".
As for the staining that others have complained about, I have not had this issue. I just spray the diaper with Biokleen foaming action Bac-Out, it's a live enzyme cleanser with lime peel extract, smells wonderful and eliminates any stains. The cleanser is sold on Amazon, Whole Foods and Smith's Grocery in the natural foods section. Hope this helps.
UPDATE--- Now the babes are 6 months and I have had some stains resistant to my beloved Biokleen Bac-Out, however, I find that if I pour a tiny bit of Oxyclean (I use the liquid) on the stain and let it sit 15 min before putting it in the wash, it will take any stains out. Even old stains.