They have something of a hive mind.
They have no individual drive or goals.
They seemingly exist on to proliferate their own kind through direct contact and then puncturing of the skin.
They move rather slowly.
To an extent injury has no real impact on them short of a rather severe injury (not quite brain-stabbing, but almost close considering their armor and resistance to phaser fire.)
The Borg are basically zombies, TNG was just way ahead of the curve on the craze.
You are dead on sir!
Don't forget what Eddington said to Sisko about the Federation being like the Borg, which I think applies!
"I know you. I was like you once. But then I opened my eyes. Open your eyes, Captain. Why is the Federation so obsessed with the Maquis? We've never harmed you. And yet we're constantly arrested and charged with terrorism. Starships chase us through the Badlands, and our supporters are harassed and ridiculed. Why? Because we've left the Federation, and that's the one thing you can't accept. Nobody leaves Paradise, everyone should want to be in the Federation! Hell, you even want the Cardassians to join. You're only sending them replicators because one day, they can take their rightful place on the Federation Council. You know, in some ways, you're even worse than the Borg. At least they tell you about their plans for assimilation. You're more insidious, you assimilate people - and they don't even know it."
The Borg are wonderful because they are the opposite of the Federation but still very much the same. They both use technology and want to move foward and grow, one through cultural and dipolmatic channels and the other through a lack of indiviuality and military conquest. Both organizations have an agenda but are opposites!
The Borg are so wonderfully written!