The nightie is a lovely soft breathable material, 100% cotton, so no irritation for anyone suffering from nylon/latex allergies and similar. I found it warm, though it is certainly only a summer weight sort of jersey material, not heavy at all. I think for the winter, some people might find it not heavy enough - if you have a cold bedroom for instance, but, as I tend to be warm blooded, it isn't a problem for me.
It isnt too long or too short and the arms are really good for those who dont like to have the top of their arms bare.
This nightdress would also be good for anyone who likes to go swimming because they could slip it on over their swimming costume when they weren't actually in the water. The white one would be nice for that, I think.