Marathons makes a fine souvlaki but you gotta eat it fresh. I made the mistake of doing take-out once and it just wasn't as good as it is fresh. And you want the meat to be hot to contrast that cool tzaziki sauce.
Marathons is definitely not a place I go to often but it's also not a place I can stay away from for too long before I get a craving.
Just writing this makes me wish I had one right now.