i lined up for midnight launch, got home and downloaded the 16.4gb before i could start playing..
the game, although 4 years newer than Skyrim, has a lot of the things that annoyed me in Skyrim. Same engine, same lighting, same sound effects, same NPC actions, etc
The game itself feels mothing like a Fallout game (minus mention of vaults and power armour)... You are no longer viewed much as a Vault Dweller/Wastelander as you are a Mercenary.
Saying that, i have 39hrs in the game so far and it is playable. there is plenty to do.
Mods will, no doubtably, add a lot more to the game as time goes on.