Well... I liked Exile. In fact I still do :]
Tessandras don't care about anything but his ultimate quest. It's linked to Mastermind. He seems to be nice guy, but don't get confused. He's BOD chief. His secret have secrets. If you like fancy, hi-tech toys, tricky missions and thinking outside the box, he is right choice for you but I assure you, he will send you to suicide mission without hesitation if it's gonna help the cause.
Caliphtys is not as dark as he seems to be. In fact Moyses would never be launched without his influence. He is power-hungry sociopath but he also express his care for ORS in his cold, ruthless way. In the same way, he has a heart. Cold, stoic, pragmatic but still a heart. He cares about his people on the same level as Tessandras. In fact, they know eachother from veeery long time and they are not that different. One prefer strength, second likes distraction. He is viable option for those, who prefer pragmatic approach and military discipline.
Tyrone is clever knight in shiny armor, but he is capable of making difficult decisions. He regreted his decision regarding Nassau incident, but he knew it was the only decision he can make. Aside from the fact that you will be part of Roaming Fleet, he would be one of the best options for you to serve under. If you have balls and affinity to give your life to save others, Tyrone will provide you very satisfying service.
And the last, my personal pick. Beautiful, focused, empathic, smart and deeply spiritual. Fleetmaster Aasira Raji is living embodiment of zen virtues, sense of community and loyalty. Nobody can gain more knowledge and experience from pain than Raji, following Nietzsche's ideas. Service onboard Anjaneya provide you with operational freedom, tight bonds with your wingmates and superiors and most importantly, their trust. Don't overuse it. Don't cross the line that defines beginning of recklessness. Raji expects you to establsh balanced approach to everything, but also allow you to handle stuff your own way... But remember, she knows you better than you know yourself and she really hate disappointment.