Fallout New Vegas is just a revenge story. It's not really that much better than Fallout 3, if at all. I remember being super hyped for New Vegas after sinking probably like 400 hours or so into Fallout 3. While I did enjoy it, just overall, it wasn't that great.
Characters AND companions? Eh, it's a mix-up honestly. Both games have their good and bad characters. Even companion wise. Fawkes was just pure awesome, and Lily wasn't that great. It's more of a give or take type of situation, really.
Some of this I agree with, but some of it I don't. The "More than 30 levels" sounds good on the outside, but you only get a perk at every other level. So even though, without DLC, that New Vegas had a higher level, it had a lower perk count. And Iron Sights really wasn't needed.
"Factions" is basically just 2 groups and 2 people. Legion and NCR for the group and either Yes Man or House. Both of them are either good or evil. That's really it. Not a whole lot to the whole faction side.
The Mojave Desert is just a desert. How much more can a desert become post-apocalyptic compared to Washington DC and surrounding areas? And all New Vegas pretty much was, was just the strip. The town part outside of the strip was essentially useless. At least Fallout 3 had some pretty interesting locations. Like Eden, Rivet City, Washington DC, The White House, etc.
More doesn't always mean better.
It shouldn't matter which game follows closer to the originals. They should be judged on their own merits. And that's all that should matter. If the earlier Fallout games are good, then they're good. If Fallout 3 and Fallout New Vegas are good, then they're good. Fallout 3 shouldn't be bad because it doesn't follow the earlier Fallout games. Fallout 3 should be good because it's just a good game.
See above, really.
Fallout 3 vanilla runs just fine. I didn't have to use any mods to run Fallout 3. I mean, yes, I had to change one thing, but that's because of the port itself. Both games run just fine on their own without mods.