best bottle warmer?

I'm nearly exclusively pumping and if I put a bottle of breast milk in the fridge the fat collects on the sides and heating the bottle ensures the fat gets back into the milk (and in my baby!) instead of sticking to the sides. We've been microwaving a cup of water for 1 min and using that- 1 min to microwave,1-2 to heat the milk in the bottle. Would a bottle warmer be faster than this? What's your favorite?