Still playing it on first run.
Loved: Victoria (Felicia Day), ED-E (beep), my laser rifle scope and weapon mods in general,Heavy Incinerators, ArchiII blasting crimson caravan cattle, Annabelle with splash damage, and BALLISTIC FIST UPPERCUTS. Also I like that I don't have to walk 20 minutes though a dull, empty, wasteland with no enemies or anything remarkable at all just to find a new location that is yet another subway tunnel like in FO3. Also I like that the quests and npcs/groups are way better designed in NV. It has way better music, and a reason to lv up barter and speech. More interesting perks. Laser/unarmed weapons are actually fun to use. Its way easier to repair and maintain equipment. You never have to go to Rivet City or listen to Moira!
Hated: Every time I hit R2 and VATS doesn't work AT ALL; its random and lasts several minutes at times. Every time my missle launcher or incinerator fails to do ANY damage in or out of vats to any enemy, which is 90% of the time. I used the incinerator a lot early on (on deathclaws at quarry) and now at lv30 it fails to register any damage even when enemies are wreathed in flames most of the time.
The fact that it crashes on average 2 times an hour. You get banned from a casino after winning ONCE at slots. There is no poker, so you basically have to play slots for hours to win anything anyways because blackjack is rigged, and max betting in roulette takes too long. I liked caravan after I figured out (mostly) how to play it, but you can't win much and if you win a few times they stop playing you.