Only remaining bugs to watch for:
-A guy called Loyal asks you to retrieve a plane from a lake. This same guy is needed in another optional quest. Once you retrieve the plane, the hangar he hangs out in actually gets replaced entirely by a new cell that includes the plane inside it. If Loyal is in the old cell (old hangar) when the cell refreshes, he's cut off from you forever. This is easily fixed with console commands on PC, and if you're not on PC, you can workaround this by making sure that it's night and he's in his house when you turn in the quest, then leave the area until the cell refreshes (the area is kind of out-of-the-way, so it's pretty much a given you won't return here unless you need to).
-The Gomorrah casino permanently confiscates companion weapons. Easily remedy'ed by not bringing them inside, since the place you dismiss your companions to and tell them to wait is literally across the street, so it's not a hassle whatsoever.
-Lever-action rifles can get a bug that makes VATS stall; not permanently, but rather your character just sits there for a good 10 seconds before firing. Luckily, the bug is visible/predictable. Basically, never enter VATS immediately after reloading. Likewise, if you go into third person view and check the gun, you'll notice the lever or bolt sticking out awkwardly as an indicator you have the glitch. Sometimes you can "feel" the glitch too in that your character randomly sidesteps EVER so slightly to the side after reloading. The bug is fixed either by holstering and re-drawing the weapon or simply firing a shot out of Vats, THEN entering Vats.
That's it. Every other bug is more-or-less fixed.
-VATS in FO3 actually maxed out your damage reduction and made you take 10% of normal damage. It made you god-like. VATS in New Vegas is nerfed and only reduces incoming damage by 25%, and only targeted enemies will see a significant slow-down.
-FO:NV has FAAAAAAAAAAAAAAR more choices to make. The quest list for New Vegas absolutely curbstomps the quest list for FO3, and the quests aren't smaller either. Hell, I'm going to be-so-bold and say that if you were to play New Vegas, you would look back on the conflicts of FO3 and call them mere childsplay, as the choices in New Vegas are lots more morally grey and not so black and white.
-Exploration in New Vegas is often the point criticized most as "the only thing New Vegas didn't beat FO3 in." Realize it takes place in a damned desert, and while FO3 had the attitude of "let's make locations fun and interesting," New Vegas had the attitude of "let's make the game realistic." Prime example: Both FO3 and New Vegas feature a community that has a shop of sorts down the street from it. In FO3, that location is overrun with raiders and resources, and likely the player's first "dungeon." In New Vegas? That shop is picked clean, devoid of almost any and all resources. Why? Because a community is right ****ing there. Of COURSE they've been there and picked it clean. Likewise, a location in FO3 could take 20 mins+ to explore, whereas in New Vegas they range anywhere from 1 minute to 10. New Vegas shoots for realism on this front.
Basically, realize that New Vegas is far more focused on questing, but in doing so, there's far more conflict and choice involved in gameplay.