The president of Sony Online Entertainment, John Smedley, has stated on Reddit, that H1Z1 will be released on Early Access in January. But he stresses, that the game will be far from finished at that point:
"What you'll be playing January 15th is a really fun game, but it's early. It's everything Early Access should be - a fun and compelling game that isn't finished. Our goal is to have you help us finish it and have it be a game we can build a large community in over time."
Smedley also commented about the similarities and differences between H1Z1 and DayZ:
"Is H1Z1 going to be better than Day Z day 1? No it won't. We'll get asked that question a lot and I wanted to be up front about it. We're not as feature rich and they have a lot of really cool stuff we just don't have yet. That being said, we're also a different game."
There will be two different versions released on launch in January. The cheaper one will cost $19.99, and the other one is yet to be announced. There will be some differences, but these were not covered in great detail:
"The difference between the two will be things like access to some of our different game mode servers (which you can get access to by purchasing tickets or earning them as well) and other specifics we'll be outlining soon."