pros - easy to clean- works like a straw as you only have to suck to get the air out and as soon as the air comes out the milk comes up so the bottle works at every angleCONS -The liners break when you try to "burp" them to get all the air out...would rather take the time to burp baby then the bottle.- measurements are WAY off (8 oz bottles will NOT hold 8 oz)- extremely hard to read the off measurements when baby has drank a couple ounces. i would ahve to pour the leftover formula into a regular bottle to see how much he ate which was bad when i thought he wasnt eating enough.- my kids had more gas with these.- leak all over everything if baby tips the bottle over on its side if he tips it upside down FORGET ANY CHANCE THAT IT MIGHT NOT LEAK