This game is so satisfying, and runs at my full 60FPS on ultra, yay! (I think even the original FO3 was shoddy and low FPS in places!). Very fun exploring non-yellow places - mountains, nice caves, lots of places with water too...
Apart form looking nice though, it is very fun I've found. Got my compadre; and am finding the battles fun if sometimes mean - Deathclaws still kick my ass (as it should be! I wasn't even level 10) and the skills I'm using, perks I'm getting are all okay - I just meander along with some neat equipment slowly progressing - no major leaps like FO3 and no need to really REALLY plan ahead skills, since you get perks every other level so skill requirements are like "Oh, I'll get that soon, better level up that skill first" - my initial choice of skills helped early on but barely affect my current play - which is mainly based on my ammo or equipment to hand, aiming at all this cool energy stuff (including nice flamers).
Man the game just does so much more with exploration, just finding things (like some of the FO3 wasteland mind you, but better - it's not all just flat), and I've not even entered Las Vegas yet

Looking forward to it! I'm so glad the plot isn't immediately "GO GO GO NO REASON JUST GO GO GO GO GET THE HELL OUT OF THIS VAULT GOOOOOO QUICK FIND YOUR DAD YOU ASS" or anything, I took most of my time just exploring the south

Not even sure what I'm going to find in the big city...also not even found the Brotherhood yet, who I've heard are around. I want my power armour but man, a simple justification for me not using any yet is not finding any! In the original game you could find (but not wear) some in close to an hour from the start of the game!
Hardcore mode also is nice - companions can die, even though I die more often then not first, and so some of the companion perks help (meaning fights are more fair generally). Ammo having weight is a nice burden, although 3 of you helps somewhat. Eating and drinking are great to a degree too - while sleep doesn't come around seemingly often enough (chugging down the nuka colas) it gives you a nice reason to keep some of the more random foodstuffs, and not allow me to carry absolutely everything I can to sell. Not too annoying (and I don't bother crafting food really) but adds enough of an edge to keep it interesting.