When deciding to use cloth diapers for our then 15 month old son, I used a trial program with several different brands of one-size and sized diapers. In the end, I picked the Fuzzi-Bunz one-size diapers and we're now using 15 of them for daytime use (I haven't switched for overnight yet). We went with a one-size diaper because we want to reuse them for the next baby without having to buy a whole other set of smaller diapers! They have held up really well so far and feel like they were made with good quality materials.
I really liked how these diapers adjust sizes using button elastics in the legs and back of the waist. I felt that the ones with snaps on the front would be really bulky on a small baby! I also liked how these were narrower through the crotch than other brands for my mobile boy. I was a little worried that they wouldn't be big enough to last until potty training, but now at 21 months old and 29 pounds they're still a great fit and we're not on the biggest setting yet!
Great one-size diaper! 
