The one and only contest I've ever won was from Home Theater Forum and I got my disc just fine. Reading your description, it sounds like a Sam Posten give-away. He's always running those and I've never heard any complaints, so I don't expect any problems either.
The movie I won was Harsh Times on HD DVD. It's not a movie I would have ever picked out for myself, and even after seeing it, I'm still not sure I'd pick it up. I guess it was a good movie, but not really my style. So that's really cool that it's actually something you want!