Iza is a little underwhelming in my opinion. The sneak stun is pretty cool but I think being ranged actually hurts her. Her damage is not spectacular and does not benefit from Obsidian's +1 magic. She may be great if you own Prince Rennyn but that is not the case for most of us. Often, using Venari Seedsmith may be better, extra damage and poison. Or any of the magic attackers. Though stunning the back character could be invaluable so my mind could change a lot if I ever get her leveled up.