The UK and US masks are the same. It is the French exclusive masks (from the "Premium edition") which are far superior, being made from resin of some sort, and also numbered. Albeit the UK/US masks have a darker paint finish to them, so both have pros and cons. But I prefer the French one by far.
I wrote an article type thing on them for my blog, check it out:
http://www.collectingasylum.com/2012...s-premium.html