You're afraid Fallout: New Vegas is 'harder, gameplay wise,' wish you were more specific. For combat, don't worry except for deathclaws. There's more weapons to fit whatever satisfies your preference to deal with your enemies. Obsidian chose to up the stats of flesh and blood deathclaws so that FNV fans can say 'our deathclaws are better than yours,' something any FO3 modder could have done by increasing stats on them. And they've got almost the same combat routine with the exception that they will hide behind boulders if you are up where they can't reach you.
They also screwed up VATS just to give the finger to bethesda, not that they don't deserve it. But they've hurt the game by making an optional feature worthless. There's iron sights to pull you into the battle and you can use pistols, shotguns, fatman, etc. under one skill. Maybe by harder gameplay you meant challenging, which is true if you activate hardcoe Mode. You will want this because 'challenging' includes reward and satisfaction, that you survived the wasteland like a boss. Oddly, Ultimate Edition gives you a magic canteen at the beginning, which is an infinite, pure water source that eliminates the water survival part by making you auto drink.
I don't know what your friends didn't like about FNV. But if they didn't use fast travel then they would have played these quests that send you back and forth along places you've already been to that are empty because you've already killed the few insects and geckos that used to be there but are now dead. So it becomes sightseeing the tedious way. It's no understatement that many areas you're sent to trek through are ultra boring because of few spawns and nada interest points.
Luckily, there are mods like Monster Mod and Warzones to address this. But forget about exploration, if you try to play it like FO3 you will be very disappointed to look somewhere that might hide a secret or lead somewhere interesting. Because most often it will be a pointless area because Obsidian ran out of time. So, play it for the story and the moderate selection of things you can do to affect the game world.