OOOHHHH.. tough question....

There are a few that I wouldn't recommend - HOWEVER - I wouldn't recommend them for my kids - who have slim hips, no butts. They would work great on chubbier bubs - so its hard for me to say that they are CRAP nappies - cos they are only crap on my kids IYKWIM? I know that they work on other people's bubs - so it really comes down the shape of your bub.

I would probably stay away from any cheap ones off ebay though - you get what you pay for.