A while ago, I would have said bambinex bamboo with nippa fastening. It was the first kit I bought when I started real nappies, slim fitting and very absorbent, they did well on my 2 girls but are now very worn as I didn't have a lot of nappies when I started. I couldn't use any other nappies on my eldest, as they all leaked.
With my second, I have tried a lot! I love the pop n gro V2, the only nappy that doesn't need extra boosting, as she is power weeing now! Pop n gro pocket, still in size 1, slim but I put my own inserts. The easyfit is not too bad, but is not as slim as I need to put extra boosters for it to last more than an hour. Love the colours of it.