If you use it "pro hobby" you may want to be satisfied with a simple one.
I think the liquid-crystal unit with sensor is not the critical part then, but it needs to be robust and comfortable. So I would buy one only after having it in my fingers and on my head - from a local store.
I've bought one where the liquid-crystal unit falls out from time to time - it does not fit too good into the helmet
but since I use it not too often, it's not a problem for me.