Fallout 4 is a huge RPG with a great story, and revamped combat.
Gameplay
First off is the combat, which has seen a very nice overhaul compared to Fallout 3 which was pretty much unbearable if not for the V.A.T.S system, and the shooting is well done and is now competent. The V.A.T.S system is not as "required" now but still fun to use, and its always a pleasure having a slow mo cam zoom in for some head pops.
Story
The story is long, and has some intriguing plot points in it under the initial one that is shown off to you. The biggest star of the game though is the players relationship with companions and the multiple side quests that flesh out the world. They made you care for your companions and gave a sense of place in this world. The factions are also all fleshed out and it makes the decision of picking which one to join and stick with a tough choice as the game progresses.
Visuals/Presentation
The visuals in the game are fine and wont blow anyone away but they are good enough and for all the criticisms the game has gotten about bugs i have not run into any particular ones except for slight frame-rate hitches every now and then but overall the game ran good enough without detracting from my experience.
Overall Fallout 4 is a great RPG with good customization, a very fun story, with nuanced companions, and tough choices to be made, and all though it doesn't feature anything groundbreaking and is more fallout, is still a great experience that you can sink countless hours into.