Kawaii's GNHW are the only diapers in our stash that are consistently leak proof. We just ordered another 12 to replace the Fuzzibunz and other diapers that started leaking once my daughter learned to walk. My husband loves how easy they are (he hated prefolds) and we both love that they keep her totally dry for hours. Now that she's not nursing at night at 14 months, she only needs one insert, but at her height of nursing through the night, two inserts would still keep her dry all night, for 12 hours.
The only downside is that the microfiber inserts tend to create stink issues. Maybe it's our hard water, but we have to strip A LOT. And the elastic that makes them leak proof can also be too hard on my daughter's skin. She has fat little legs and the elastic cuts into them sometimes, leaving angry red welts. We switch to disposables while we're fighting ammonia or welts.
If I were giving people diaper advice I'd say to definitely try these as an overnight option, but maybe keep some less tight options for day time use. Our other diapers leak more, but they don't leave the angry red marks. (The bulk package pricing is also incredible. I bought 12 for around $6 a dipe, including shipping. They come with two inserts and a double PUL layer)