Can't comment on size 0, but we have Kissaluvs 1s and 2s that I found used. They are GREAT. We only have a handful and usually use GMD prefolds, but we save the fitteds for long "outings".
I strongly recommend Thirsties Duo covers (the expandable ones). Sprog's first size lasted from birth to 5 months. She'll be wearing her current size 2 ones through toddlerhood, I'm certain. They fit very, very well and have since she was born.
We also had a few regular Thirsties covers that we picked up used. They were fine, too. But the Duos are trimmer and of course, you get twice the life out of them.
Often bumbling mother to baby girl "Sprog"
Born November, 2009