As for the regular game, this game was intended to be personal and they made it so. Dumped 20 hours in, only hit a few of the main quest(been hitting the side quests, how screwy is the disk system?!?) but the level of depth is amazing. I couldnt imagine playing this game without the first 2.
Edit: Krogans are so unbelievably overpowered. Damage bonuses, extra health(alot), and oh yeah, 1 shot melee kills on just about anything. Absolutely insane.