I like them a lot

they fit perfectly on the imperial guard models and look really good on them. I´m using the US Gas mask heads for my stormtroopers (you can see one of them in my avatar...) and the plain US steel helmets (whit and whitout camouflage netting) for my regular guardsmen.
I changed heads on the baneblade commander from a US gas mask one to a German officers head whit gas mask. I liked the cap better