^^I don't think Miranda chose her job because of "prestige." She chose it because she's a career scientist, an explorer. That's fundamental to who she is. Her goal isn't to advance her career, it's to discover new worlds and new mysteries of the universe. That's been her life's work, her identity, since long before she became a wife and mother. It's not just a career, it's a calling. Just as it has been for Kirk and Spock and Picard and Riker and so many other Trek characters.
I understand part of that - yes, she's a career scientist, so she wants to continue with that career. But hey, anyone who's had kids knows, you make sacrifices for them - and you want to. She can't find a ship better suited to her family? A posting closer to home that allows her to keep her 'identity' (again, becoming a parent creates a whole new meaning for 'identity' here - I thought I knew what was important until I had kids) and her family. I do think there is an amount of prestige going on here - because I think she could still have her career and balance it out with her family better - but it's the ENTERPRISE!
For what it's worth, I'll take Miranda (for all her faults and my reasons for disliking her despite every author's attempt to convince me otherwise) over Riker's number 1 on Titan - flawless, overeager, so forgettable I can't remember her name even when I finished Gods of Night only a few days ago (and I've read most of the Titan books too).