Pros: Inserts are very absorbent, versatile, and do not stain easily.
Cons: Covers tend to allow leaking around the legs because of non-snug fit.
I bought several flip systems for my now 18 month old and used them for several months. I ended up selling the covers with just one insert per cover, keeping the extra inserts for myself. I love the inserts and use them now with my other covers. I wish they were a little bit wider because the poop can miss it sometimes on the sides. I don't think I have one insert with a stain. They just never stain. There absorbency blows everyone else out of the water though.