Positives:
Small, practical, easy to use, good construction, heats to the right temperature, does what it promises, easy to transport
Not so positive:
Time for a bottle of milk (~250ml) ~9-10min (maybe it would help more if it heated in 5 minutes)
I do not consider it value for money, in the sense that it is a very simple machine for the 30+ € it costs. Of course, it is a matter of supply and demand, so it is probably at a decent price for these types of products.

It has served us unbelievably well on trips, as all it needs is a little water and an outlet.
You put the button, for example, on the bottle indicator and the bottle inside, and the light will turn off by itself when it's time.

Cheap Chinese construction that does not heat up to the desired temperature with enough accuracy to trust it.

Fast and very practical, if you want to keep the milk at a satisfactory temperature or defrost frozen. The only downside is that if you put the indicator on the bottle (for milk), the temperature is too high to give it directly. So, you have to find at which indication it is suitable for immediate administration. Otherwise, very practical.

Pros:
Brings water to the desired temperature for immediate consumption.

Cons:
Easily catches salts and the metallic surface is difficult to clean. Avoid using a sponge as it will easily scratch it and it will appear as if it has caught rust. Use white vinegar for cleaning.