Mentioned this in shoutbox yesterday when Bethesda sent an email, making a quick post since the deal is now live.
Note that the base game is free to play, DLC is not included but you can always mod to your hearts content with either Steam or NexusMods. User reviews are mixed due to the hardcore following (which I understand) and most the mechanics are dumbed down, too much settlement busywork and annoying characters - however I really enjoyed it and have over a 1k hours which is more than normal due to the numerous mods I have installed and my passion for building huge settlements. There's enough DLC content and it's good enough quality in my opinion bar Contraptions but the best DLC is no doubt Far Harbor.
Fallout 4, OpenCritic score of 87%, is free to play over the weekend and -67% off base game and -40% off season pass - http://store.steampowered.com/app/377160/
If you're still not sure check out the game yourself and grab some mods and I suggest the following, none of these will cause game-breaking issues compared to the other mods:
MOD: Achievements - simply allows you gain achievements with mods, relies on F4SE.
MOD: Unofficial Fallout 4 Patch - essential bugfixes and balancing BUT only install if you have ALL DLC since it relies on other assets.
TOOL: LOOT - same tool you use for other Fallout and Elder Scrolls series of games to ensure optimal priority of mods load order
MOD: New Dialog - aimed at showing what the character would say than annoying you with answers you wouldn't say
MOD: Improved Map with Visible Roads - what it says on the tin!
I can lead you deeper down the rabbit hole (more complicated) and quickly mention DEF_UI for more of your inventory to be displayed without RSI-inducing scrolling, Place Everywhere which makes building less frustrating and requires F4SE which is why it won't run on consoles, and Spring Cleaning is safe to use (much safer than Scrap Everything) for those wanting perfect settlements or OCD sufferers alike. Like with any mod and especially these: read the description carefully, watch videos, and check the comments.