How easy is it? Fill the bottle with as much water as you need (2, 4, etc ozs), pour the water into the machine, press the heat button and while you wait you can scoop the amount of formula needed into the bottle. Once the machine beeps you simply press the orange button and it dispenses the perfect temp water into the bottle, put the lid on and shake. Much faster and safer than boiling water or using a kettle.
How do I warm other things? You can warm your jars of baby food up in the Bib'Expresso as well with the Bain-Marie mode. You simply fill the water reservoir to the max line indicated, place the jar of food into the reservoir and then you choose one of the two warm buttons. This also works for pre-mixed bottles and breast milk.