Jason13 has a point of it being a matter of opinion, but accuracy to the source material is undeniable and there are certainly some that are more accurate than others. The most accurate that I have personally seen are Se7enSins (endorsed by someone on the fx team I believe) and Simon.
To be honest, After comparing multiple shots of the hero, Stunt mask and so on I must say Simon Brandolino, SevenSins, Remzap86, and Horror School Customs do the absolute best. JC is amazing when it comes to H1 and H2 masks but I just don’t think his H40 is on the same level as these guys.