I'd probably find Sam slightly terrifying if she was real and we met in
person, but as a character to write she's great.
Sam / Jamie is fairly obvious — though she didn't have a lot of
alternatives in her one and only story. Other than that, I think she
might get on quite well with Mickey.
She seems to get on quite well with Jean Rock, in canon and fanfic.
And, of course, in the Jamie's Angels stories I've teamed her up with
Jamie, Victoria, Zoe, Isobel and Gia Kelly, all at once.
I'm not sure there are unpopular opinions about Sam, either. Though my not-entirely-serious theory
about her being Heather McCrimmon's grandmother didn't meet with
widespread acclaim.
I wish her one serial existed and had been released on DVD with Frazer
Hines and Pauline Collins on the commentary track. Also, I'd like her to
have become a proper companion — provided she'd been able to
keep her attitude and her accent, and not been watered down into a generic
screamer.
Sam