I understand the obvious price difference, but would there be any drawback to buying an X valve used? Outside of maybe some anno rub?

Also, if the ULE body is Angel threaded feedneck, which of these in this list is "Angel threaded" =/
http://store.customproducts.us/index...6&categoryID=5

I am stumped, but maybe its a simple question to someone else.
Thanks,
Jason