We have one and DH initially thought it was a waste of space but quickly became a bit attached to it like me.

It does throw off some light, but if I need to search for a dummy in his cot or something like that then I use the nightlight that came on top of the baby monitor. So if it is a nightlight you are after, the grobag egg probably wouldn't do the trick, especially if the room is really cold and the egg is blue.

I wouldn't have spent my own money on an Egg, but used a gift voucher because a friend loved hers and I thought it looked cool. And I absolutley love it. Yes, its a gimmick, but it is so easy to walk past his room in a very sleepy state and know whether it is too hot or too cold. We have such big temperature changes here though so we actually use it. Not much point if the weather doesn't change much from one day to the next where you are living.