I must be the only one that likes Playtex drop-ins, lol!
Its got a very wide nipple, and because you burp the air out, there is absolutely no air in the bottle and your LO does not have to break the latch in order to let air back in like he did on some other bottles.
To top it off, they are incredibly easy to clean! Yes, buying the inserts could get expensive, but I'm not going through them at nearly the rate I thought I would! I actually have a lot of liners in the 4oz size I need to find a home for!