Even though I nursed my 1st daughter I did supplement with formula or bottles of breast milk. I was given this item as a shower gift and I have used it daily for the past two years. We have another baby now and we use it all the time.
I don't believe in microwaving babies milk for several reasons. One is that hot pockets can be created by uneven heating. Another is that some resources report a breakdown of nutrients in foods heated in a microwave. So for me this is a great and easy alternative. The opening of the bottle warmer is wide enough to fit some of the wide necked bottles such as Avent brand bottles.
To use the warmer there is a small measuring device which conveniently hooks onto the side of the unit. Depending on the amount of milk you intend to heat, you measure the specified amount of water and dump it onto the heating element of the warmer. You place the bottle in and turn it on. The warmer clicks off when heating is complete. There is no beeping or other annoying noise, you simply wait for the "on" light to go off and you're ready to go.
The one drawback with this item is that the heating element is made of some sort of metal which seems to give off a rust-like substance which is a bit of a nuisance to clean. To clean it I put a about 1/4 cup of water in and turn it on. I let the water boil in it to loosen the debris and then wipe the rest out with a paper towel. If cleaning things doesn't bother you than there are absolutely no complaints about this warmer. It's been used multiple times a day for just under 2 years and has never failed us. That's pretty impressive in my book. A great vaule for money considering it's become a part of our daily routine.