Enclave enabled makes the game tougher, much tougher actually if your out cruising in the wilderness.
Instead of just the random bear, raider, or deathclaw you have 2 - 4 guys in power armor and plasma guns that shoot first and ask questions later. And while one ties you up, the other 2 will be trying to flank you. Personally I don't wear power armor myself, slow and clumsy. So 3 good hits from a plasma and your loading a saved game.
Granted some make some parts of it easier, some just make it more interesting, or more convenient.
But thats the nice thing about mods, suit yourself.
New one posted today lets you sign up as a caravan guard, pays you in cash or karma for a completed trip.
Deathclaws and Yao's still scare the bejesus out of me at times. Especially after dark. All of a sudden your going "did I hear something breathing down my neck? Was that a footstep?" GRAWWWWWWWWWWWWWW Aww crap. Keeps me coming back for more though.