I picked them up early because without them that assassin at friendly arm inn would slaughter me.
Since my char is good, I should really dump them at some point. However question is when? Montaron is great with his sling and xzar is a Mage. My main concern is losing a Mage. I currently building up my party before we hit the Nashkel Mines and I've seen quite a few recruitable NPCs, but any recommendations to replace Xzar?