I've played through the game six times, one for each class:
Nicolas Shepard (Headcanon playthrough): M!Shep, Vanguard, None-Tali-Tali
Kenny Shepard: M!Shep, Adept, None-None-Steve
Shannon Shepard: F!Shep, Infiltrator, Kaidan-Kaidan-Kaidan
Alexander Shepard: M!Shep, Sentinel, Ashley-Ashley-Ashley
Rosemary Shepard: F!Shep, Engineer, None-Thane-Samantha
Timothy Shepard: M!Shep, Soldier, None-Miranda-Miranda
I tried Garrus's romance once, and didn't care for it. Also did one when there was no romance at all
I think M!Shep has better dialogue, both in the romances (the prime difference between the sexes) and the expressiveness. F!Shep always sounds vaguely pissed off, which is good when Shep is pissed off, but not when she isn't. When Hale did good, however, she did real good. F!Shep had some pretty crappy romances (Jacob I had no interest in, Thane's was okay, but short until Citadel, Samantha lacked content, and Garrus's was wholly unbelievable)
As for who belongs in charge, the person who belongs in charge deserves to be in the charge, the one with proven experience, vision, and charisma to make those under him follow him. (I'm aware I used a masculine pronoun, it's proper English to do it that way, it's not a qualifier)