Conversely, I have about twice the hours in FO4 as I do in New Vegas (and many more than FO3) and I'm still on my first play through of FO4 and haven't finished the DLC yet. I've played through NV twice and done all the DLC.
So, while there's stuff I like about NV over FO4, I certainly got my money's worth out of the game.
FO3 was the weakest of the new Fallout titles in my opinion. Played the main story once, no desire to go back or hang around the world. And the original FO3 ending has to rank among the most asinine and poor game endings in history.
I think the main issue people (including me) had with Fallout 4 wasn't that it was a bad game. Plenty of content, heavily improved gun mechanics (like actual recoil), though not amazing but still better graphics, OKish story, settlement building, somewhat interesting world (didn't grab me as much but still). It was a terrible (new-gen action RPG/FPS Bethesda-ish) Fallout game and the 3 main reasons I have with the game was:
1. The lack of dialogue options to convey YOUR character's opinions of the world, people, etc. ("yes,no,more info,sarcastic" and that's it);
2. The lack of non-main story related consequence for your actions (e.g. dialogue before you enter Diamond city for the first time; no spoilers);
3. The premise of the story locks your character to "concerned father" and hammers it home quite heavily throughout it all.
These 3 things completely ruined my game since I can't roleplay (around 50-60% of enjoyment comes solely from that; even more enjoyment is enhanced by roleplaying) as a mad explosives expert, nor can I be the saint, making my duty to save the world. I can only be a good concerned father or a slightly dickish concerned father.
You gotta give credit to FO4 though since I actually managed to log 26 or so hours before quitting the game and never playing it again, while with Fallout 3 I played around 15 painstaking hours, uninstalled, reinstalled months later, installed Fallout: Wanderer's Edition, Marts Mutant Mod, some weapon ironsights mod, a few graphics overhauls and plenty other smaller mods, at which point I actually started to enjoy the game and logged quite a few hours (Steam doesn't count hours if I launch it through FOSE).
As with NV, I never actually touched the vanilla version (I think) and instantly installed Project Nevada alongside many other mods and had a really pleasant (albeit shorter; should probably get back to it some time) experience.