I window-creeped a bunch of Feral Ghouls in a small cabin, right out of Night of the Living Dead. And it was great.
There's no doubt in my mind that if Fallout 3 sported incredibly solid writing and were more visually polished, I would prefer it. Even then, from my time with 4, just moreso. 4 would still be able to hold itself up on it's own merits and I can see myself getting a loooooooot of playtime out of it. Hell, I'm already planning my melee build for the next run!