One word. AMAZING. FABULOUS. FANTASTIC.... oh wait, that's three

They are so so so so so good

I was lucky enough when I bought my 2nd one (at a baby market) to meet the woman that created them - it was fascinaing talking to her.

It has helped us so much - after buying it and it making such a difference, that's all I've bought for baby shower pressies, etc since

IMO you definately need more than one, she does suggest to use them for all sleeps (day & night) so bubs get used to them as a general sleeping routine, not just at night... so you need at least 2 so you can wash and still be using them!

Other tip I can give - the Houdini is fabulous, but the material is a lot thicker than the others, so I've found it to be too hot with the hot weather we've been having. The other ones have been fine though