Decisions are just as important to
Fallout: New Vegas's mechanical underpinnings as they are to how your personal adventure will eventually turn out. Character stats are tied to the S.P.E.C.I.A.L. (strength, perception, endurance, charisma, intelligence, agility, luck) system. These stats determine everything from how much stuff you can carry to weapon proficiencies. Points are earned with every character level. You'll also earn Perks, allowing further customization as well as the chance to balance out statistical deficiencies.
Party members offer additional stat boosts. You can have two at any time, though they aren't that useful. It's easy to lose track of them and there's no way to quickly find them. After a few hours with my first companion, I ended up swearing them off altogether. Although they can even lead you down certain story paths, it isn't worth the hassle of having to babysit.
Shooting was Fallout 3's weakest element. Playing in VATS (Vault-Tec Assisted Targeting System) was effective, but the act of shooting things wasn't much fun. New Vegas adds the ability to aim down your gun's sights. Though it doesn't bring gunplay up to par with other shooters, the upgrade is immediately noticeable. In Fallout 3, I spend a majority of my combat time using VATS. In New Vegas, there was a 50/ 50 split between the two modes.
Just to address an issue I've noticed cropping up around various gamer communities, there are numerous reports involving glitches and other bugs. Though I didn't encounter anything worse than a freeze-up or two, just be aware that the possibility for bugs exists.
The similarities between Fallout 3 and Fallout: New Vegas are fairly obvious to the point you could probably get away with labeling it "Fallout: 3.5." To this point, your enjoyment of New Vegas will depend greatly on your opinion of Fallout 3. Changes have been made (mostly for the better), though they aren't so drastic to win over players who weren't into Fallout 3.