I did not like Obsidian's Fallout: New Vegas at all compared to Bethesdas masterpiece of fallout 3. I played both from top to bottom, in and out. Every mission every dioluge option. FNV was boring in comparison to F3 and of course FNV had better dioluge, weapon handling. crafting, etc it was made after F3 and had all of F3's ideas just revamped
To each their own, but to me, Fallout 3 only offered fun exploration.
There were no choices in the main quest. There WAS, but it was so ridiculous that you either played the good guy, or your character was the biggest psychopath on the planet as he had NO motivation for taking the bad route; the bad route meant you killed off your own allies to benefit a group that wants you dead and killed your father.
There wasn't any weapon balancing. This isn't because FNV used F3's engine, this is simply a different philosophy by Obsidian and Bethesda. If you play the Elder Scrolls and you find Umbra or Goldbrand: you're done. End-game weapon right there. Same with Fallout 3: A1-32's Plasma rifle, Lincoln's Repeater, Alien tech or a sniper rifle. Nothing can compete with these, nor did Bethesda make an attempt to let anything compete with them. Obsidian on the other hand made sure each gun had a strength and a weakness. Maybe a gun was accurate but had a slow reloading time, meaning that it fit PERFECTLY for a character with Fast Shot and high agility, but was worthless for a character with Trigger Discipline and low agility.
There was no in-depth story. Don't get me wrong, there was one, but it was copy-pasted from FO1 and FO2. There was nothing original about it, and the story was presented in such a black and white, good vs evil way. FO:NV on the other hand has an interesting mash-up of several social-economic theories and philosophies, along with several side-quests or DLC storylines that are equally as interesting.
There were crap perks. FO3's perks were all free skill points and a few powerful perks that literally anyone could grab. The result was every character felt the same, because the free skill perks did absolutely nothing and the good perks were few, accessible and the obvious choice. New Vegas has dozens of SPECIAL, Perk and Trait combinations that work in all sorts of different ways. The game also had the common sense to LIMIT your perk count to one-per-two-levels, meaning you needed to choose wisely and couldn't specialize in literally everything. Again, this is NOT because Obsidian was simply able to expand upon Fallout 3's base. If anything, many (good) perks in FO3 were taken from FO1 and FO2, and the perks of Skyrim have proven (imo) that when Bethesda is left alone to come up with their own perks, it's not pretty.
As I said, exploration in FO3 was fun as hell, but the quests paled in comparison and the storyline, character customization, and weapon balancing just can't compete. Their storyline was faaaaar less complex, the character customization simply wasn't as detailed and I don't even think FO3 HAD weapon balancing or attempted to have it; the moment you got Lincoln's Repeater or A1-32's Plasma rifle, you were set. The problem is that by the end of the day, exploration gets old. You learn all the interesting locations, and once you've been there, done that, the game is done. Character customization, weapon balancing and a good storyline that can be seen from multiple perspectives though? That's an excellent formula for providing a game with incredible replay value.
Just my two cents.