I doubt that Steam won't have cloud or achievements.
The GOG version has it.

We have no official system requirements yet. The only specs we've gotten thus far was what was used to run the demonstrations last year. And that hardly shows us what is needed to run the game.
The only thing we get out of that is; anything as fast or faster should be sufficient to run the game.
I repeat. Minimum/recommended specs are not released yet.

Another statement by CDPR:
CDPR is not sending out invites to test out the game. If you recieve one, it's a scam. Ignore it.