I just downloaded this mod last week, been playing around with it.
I like the additions of the new metals and such, as well as the monsters and weapons and seeds and whatnot. Seeing all these new plants and foods has been really cool, especially since it's motivating me to gather overland more, which adds more diet variety.
But DAMN those ORCS are nasty.
I just got hit with my first siege and they killed...13 Dwarves.
I had a really nice trap hallway all set up with cages and swords and spears, but I'm pretty sure you're changed around the AI a bit, haven't you?
Or something.
Because instead they walk all the way around my Fortress to a secret entrance I built for the fisherdwarves, go down the stairs, smash open a locked door?! and then proceed to murder my entire crew. My Champion military is all dead, and the only reason I survived was my 6 legendary Miners and Artifact makers that I drafted.
So I know that they at least know to avoid traps, and smash doors, both of which were surprising and frightening to me.
Also, I saw like 6 of them walk across my entire trap hallway at least 2 times each without a scratch. Which is really surprising, since they passed at least 3 cage traps and 3 weapons traps each time. Do Traps work less in this mod and are ORCS immune to traps or something?
Luckily, some migrants just arrived with a Dungeon Master, which is nice.
On the con side, my super ranger is dead, which is disappointing, since he was hunting unicorns (He already got one and was about to bag another when the ORCS came).