I will soon be using these on another baby (2nd child in this set of covers). The only covers I wil be using are my Nikkys, a couple ruskavilla wool longies, and hand-knit wool covers I am making myself. This will be my 4th child in CD, and it has come down to what I love most & what works best. With my first 2 dc, I could not afford Nikkys. After finally using some nb poly Nikkys with #3, they are the only non-wool cover I would choose from now on.
They hold up very well-- mine still look brand new with zero visible wear. They also wash up beautifully-not one stain.
I especially like the NB size, as new babies are so very hard to fit in the early days, and the NB size take baby from day one to size one with comfort and ease. They are trim-fitting & not bulky at all (unlike some wool covers). The leg gussets are PERFECT-- for some covers this is a hard-to-design area-- Nikky gussets are soft, comfy and stretchy-- they did not leak, even on a skinny-leg newborn, and didn't leave red elastic-rings on her thighs when she grew and got chubby, either. I don't recall ever having one diaper blowout with Nikky covers.
I never expected to like a manmade fiber cover as much as I like poly Nikkys! (The wool and cotton Nikkys are great as well, a good company with a long tradition of quality products)