Is this any different from other isometric Rougelikes? Because there are tons of them.

Well, if you like to read there's a lot to read. Jeff Vogel is a really good author, most of the game is told through text alone, if you care to read it. The game world is also huge and the storyline isn't linear, it's like the 2D oblivion or Morrowind in the sense that you can do whatever you want (well, sorta), and have people react to you. I think the story though got more linear with Avernum 4 and 5, It was way more open at Avernum 3, I believe.

I've played the Avernum series a lot, since the exile days!

I played em back when they were Exile.  Pretty good games.  I reeeeally hate the new look though in the more recent games!

I agree with you. They went a more geneforge look, even using the gfx from geneforge.

My favorite I gotta say is Avernum 3 it kicks so much ass! I've been playing it now with a one-man-team, a slith named Sharz. And it's really difficult, fun and immensely rewarding. I'm currently doing the golem quest, and it's been slow and I must play carefully for if he dies - game over!