I have used them on both my babies for about 4 months, basically until they are old enough for their one size diapers. They are versatile, easy to wash, can be used as burping cloth ir even just to put under baby for tummy time when they spit up. I now use them as inserts for my Bumgenius 4.0 diapers. Easy to use, my husband actually likes how versatile they are and has his own prefered folding technique.
I would say that they dont really fit until 20lbs though. My kid is now 16 lbs and doesnt fit in them and he is not a big baby at all. They start to get small on the sides and it gets hard to "Snappi" them.

All in all VERY happy with this product. Im gonna have to find new ways to use them once my boys are out of diapers. Or sell them. They can be used forever frankly and the absorbency becomes better with time.