Ok, so I haven't played Fallout 4 yet since I'm a poor sperg whose saving for a new PC to run it and a plethora of other games on it. But I got Fallout 3 recently, and I'm in love. Before that I had only ever played New Vegas, and I love so much of it, but at the time hate so much of it. The Capital Wasteland is a wonderful death trap which is infinitely better than the Mojave in my opinion. The feeling of desolation and total annihilation makes each moment of exploration glorious, since when I walked out of vault 101, I was not sure what the fuck I was mean to do.
The setting, the small towns and the landmarks make this game fun for me. I enjoy having to explore the abandoned subway stations, and having to launch street to street urban fighting against super mutants and Talon Company Mercs. Its also enjoyable to simply run into a bandit camp and shoot the hell out of a raider camp, or purge the slavers of Paradise Falls. There's also great cinematic moments, like running out of Raven Rock as Enclave troops try to fend off their own defenses, and fly out of corridors, launched by explosions.
The game did frustrate the hell out of me when I came to the realization there was no jury rigging perk, and that there were no companion quests. I wanted to badly do a quest where I could free Charon from his contract, or one where I could maybe romance my way into Paldin Cross' heart. That coupled with the rude awakening to companions possibly dying frustrated the hell out of me.
Overall, I think its entertaining and refreshing, though that being said I had played New Vegas on and off for quite some time so maybe it was fatigue from that? Either way, haven't yet finished the game, but I hope to do so shortly because it is pretty fucking awesome.