Judging from the angles of the few pics on here, Vader's mask looks good, but that helmet looks way too big.
I keep seeing Dark Helmet from Spaceballs.
Here's some other low angle screenshots of him...
I'm a Star Wars nerd just as much as the next guy, but I can say that I'm not one of those technical nit-picky Star Wars nerds. However, it's kinda easy to spot a big helmet, and I think this Hot Toys helmet is just a little too big.
Still a little hard to judge, so I might be wrong, and maybe I am once we start to see different angles of this.