I play the Ortega's primarily, and I, for one, greatly dislike Santiago.
Nino is a godsend for the way I play. I take down my enemies before they can even touch me through a combination of alpha strikes, Nino's 16" range, and Perdita's and the Enslaved's ability to Obey.
Part of what makes Nino so excellent is his capacity for board control. He has a 16" range, and if you get off "In My Sights," he has CB 9 and the ability to get off Trigger Happy or Headshot. If you want something dead, it will die. I've had instances where, turn 2, I've mowed down 3 models with Nino alone. However, he is difficult to position and when he gets into melee, he dies fast.
Santiago is far too slow for what he does, in my opinion. (I'm doing this all from memory, so I may be a bit off with numbers). His walk is only 4, which is the same as Nino's, yet I do not see his ability to hit as hard. His CB is lower, and he has no built in way to change it, like Francisco does. He's no better in melee than he is at range, and at range pretty much all of his family is better than he. In melee, Perdita and Francisco are better (in my experience). I also dislike the fact that he has to be half-dead in order to get his buffs. It promotes reckless play with him and makes it far too easy for him to get focused. Maybe I'm missing something with him, but as far as my play style goes, he is not worth the 7 points. If he was 5, I would take him in a heartbeat. But stone for stone, I greatly prefer Francisco and Nino.