Well, I enjoyed both, I did not love either. For reference and so you can put me in a little boxes I loved Morrowind, disliked Oblivion and enjoyed Skyrim.
Fallout NV is way better written and its story is way more interesting (+makes sense, feels "Fallout-y"). More than that - Fallout NV is probably one of the RPG with the best "world-design" : it feels like a comprehensive world with its economy, its "cultures", its encompassing political and ideological struggle that go through the whole Mojave. The war between the various factions has its recent history, which you can connect to locations you can visit or people you can talk to (
eg the defeated Khans), it has its strategic targets (
not only the dam but also eg the power plant). Exploration is not so much finding pretty places, it is adding pieces to the puzzle of the world you know, until later in the game you are the one creating the puzzle.
Obviously, the fact that FNV have factions and that the world evolve depending on your action / faction choice way more than in FO3 is the cherry-on top... but then this part feels rushed as NCR is way more fleshed out than Caesar and you can reset your faction standing at some point - so the faction choice is not critical in making the world comprehensive - it is everything else.
Similarly, I don't feel the individual quests taken in isolation are that much better than FO3 - I actually find them in general LESS interesting - but they connect better in the global world, whether they kind of float in a bubble in FO3. This gives the quests an extra purpose they don't have in FO3.
On the other hand and as a consequences of it, the cities and "place of interests" in FNV are usually boring and uninspired in terms of look and while the main quest feels less direction in FNV than in FO3 you are forced (in a very organic way) to travel counter-clockwise to reach New Vegas. Seeing NV towers in the distance and the frustration of it being within grasp but not there yet works very, very well, but the game feels less free in that regard than FO3.
FO3 has terrible "World-design", but it has way better city architecture and "level-design" in terms of pure short-term exploration, and as I said the individual quests are just as good if not better than FNV. The problem is that lacking world-design, each city, and really each location is a bubble with little or even zero connection to the rest of the world. In this regard, it is really Oblivion with Guns : not only because of the general
"pick a direction, find adventure, don't think too much" but also because Oblivion never bothered having a world that made sense in terms of how the places and people and whatnot articulate with one another. Thanks to this, FO3 feels less directive because the game designers did not have to care whether player encountered "bubble-place #7" before or after "bubble-place #3.
Consequently, I played FO3 8 years ago and FNV 3 years ago - I have NO recollection of the story in FO3 except that I am looking for my father and there is some poisoned lake and a giant robot at some point, but I remember fondly the "dungeons" and other locations (
that Mirelurk place near the river, the virtual reality '50 America, the ant tunnels, Megaton and really all the cities, that early game supermarket near Megaton, that tunnel with all the kids, Oasis, Washington DC,
the Enclave base, ...). I don't think I really remember any place in non-DLC FNV except NV itself and the Hover Dam, plus the two military bases (NCR and Boomer). On the other hand, I remember very well the storyline and some of the characters of FNV, and the look of the general map.
Side note : I don't find the FO3 tutorial that bad, it is fun the first time for sure. I assume it has no replay value, but then FO3 has IMO no replay value either, so...
Last items :
Fallout 3 DLC are terrible, with
The Pitt reaching at best "OK-ishness", whereas FNV has one solid-though-often-frustrating-and-YMMV DLC [
Dead Money] and one outstanding DLC [
Old World Blues]
BUT
The Fallout 3 radio is way better than the Fallout New Vegas radio
All in all, I believe that FNV is a superior game but I can see why people would prefer FO3, especially if they don't care much about the Fallout lore and prefer "short stories" of sorts rather than a full campaign
. FO3 is about being a mercenary, FNV about being a stakeholder.
About "world-design" vs "level-design"/ originality, you can have both - Morrowind obviously comes to mind, or to take a less popular / well-known game that will give me RPGcodex cred, the Dark Sun games (or the Dark Sun P&P universe). Even Skyrim, for all its flows, was adequate in this regard.
