I love Marcurio, he and Erandur are my favorite followers, but I haven't really ever used Marcurio, sometimes I just marry him, because of his chain lightning problem. Are there any benefits for choosing him that makes his chain lightning worth it?
I absolutely adore Marcurio. I have used him quite abit. He is pretty powerful, he's gotten me out of several sticky spots, is pretty good about staying out of the way and he is also a talker. I happen to like a talker, though lots of people don't. His chain lightening never really bothered me. My combat tactics mean I am close in and taking damage from enemies anyway, so whatever damage I do take from him just gets thrown in with everything else. I just take healing potions and move on. Also I don't use much magic, so I don't get any effects from that either. I get a kick out of watching something I'm battling get blasted out of sight by one of his spells. If you use magic as a primary combat tactic, then Marcurio may not be the best choice, since Shock affects magic, but otherwise I think he's one of the better followers. He's pretty darn charming and I've taken to marrying him as I reach his cap, just to keep his company. Granted, I no longer use him as a follower and make sure he's in a walled town at that point. Ive had one too many husbands eaten by dragons and I have no desire to lose another that way. Funny story, he got kidnapped by vampires during one playthrough. He wasn't a follower and I hadn't married him (much to my regret) but those vampires got my wrath for daring to touch my Marcurio. Weirdly, he referred to me as "my love" when I freed him. Stole my heart, admittedly, but it was an interesting glitch.