If anyone is interested, I have the actual Crashe Cap. I got the light weight knit one, basically the one for summer, and I wear it with a fairly thick knit hat over it. The cap itself does not come down low enough in the back for my liking but the knit hat worn on top makes a nice roll of padding at the base of my skull and then over the whole thing.
As others have said, the protective panels are very hard. If I hit my head with my current set up on, it would be soft first then the hard panels, I believe it would give some protection, certainly better than nothing at all. I have fallen with it and it stayed in place fine (did not hit my head but did fall backwards), but I do not think the Crashe cap alone would stay in place because it is too short, it basically needs something else over it to help it stay in place. That appears to be true of both the winter and summer models, knowing I would have to wear something over it I did not want the heavier fabric of the winter model.
That said, the biggest issue with my set up is that it gets too hot. I did not wear mine much of the summer due to over heating, now that it is getting a bit cooler and the rink is emptier, my head is getting cold and it is nice to have it on.