For some people it's great but for me and a few friends of mine it's not. It's fun at first but the game changes completely after several mods and I find myself not enjoying the game as much after a while.
How much the actual core game play changes with mods, is up to you. That's
one of the great things about them. You can tailor your gaming experience the
way
YOU want it. Just a few graphic tweaks for more bling? Some
more weapons and armors because that is what you like the most? Or a huge
complete overhaul because you feel the vanilla game is severely lacking in many
departments. Or create the cutest little nomnomnom Elf girls from your dreams
*cough-cough*, it's all up to you. How much, how little, and what...it's a Win-Win!