We don't have one. we put a big glass in the microwave and put the bottle in the glass of warm water- works fine. I know others who have bottle warmers and like them...
I used mine...I used it mostly to take the chill off of my expressed breast milk that had been in the freezer and thawed in the fridge. When we switched to formula, I made each bottle fresh at room temp and it was good enough. My best friend's daughter wanted her bottles warm though so she wound up having to buy a travel warmer for her car.
I got a lot of use out of my "freezer pack bottle bag" If I made a fresh bottle when we were out and about and she didn't drink all of it, I could store the bottle with the freezer packs and it would stay good until she wanted it, or we got home and I could put it in the fridge. It was especially great with my bottles of breast milk because those were already "made" but needed to stay cool until she wanted it.
I never needed one, I just ran the bag or bottle of milk under warm water for a minute and it warmed up quickly.
I'm the same as GRose, frozen breast milk under warm water is all you need. It will warm it up just enough. Also they say not to put breast milk in a microwave...I know a bottle warmer is a little differant. But warming breast milk up to much will break up the vitamins and stuff like that in it. Cold or warmed with water is all you will need.
i just use a glass or warm water either from the tap or heatedup in the mircowave. My little one tends to do better when her bottle is warm. She is now a formula fed baby ( i had issues with bf'ing her wasnt getting enough for her) usually warm water works well to warm up bottles. When i am out with her i just ask for warm water if i am out eaitng or something.
Obviously don't have a baby yet But I think that the bottle warmer is good for convenience but you can do the same by putting the pottle in a pot with water on the stove and heat it for a few minutes. I would avoid using the microwave as much as possible, it damages the consistency of the milk.