With a DS of 14 and a DD of 11 I can confirm that the DS is so much easier! DD is in Year 6 and is now looking forward to starting at a new school with none of her old friends going there. The last few months have been a nightmare with the fallings out/ b****ing/ etc which are still dominating what should be a lovely time at the end of Primary school. I never had any of this with DS. Boys are so straight forward and girls far more complex, but isn't that true when they're adults as well!!
There are obviously exceptions to all this but talking to other Mums (Dads don't seem to notice as much!) it appears that the majority conform to the above.
I have 3 girls.The amount of squabbling they have gotten involved with has had more to do with their personality type than their gender.
As I only have girls, when there are tough times, I don't think "that's because they are a girl" , rather I see it as a combination of factors around their personality and how others interact with it.
I too have a year 6 daughter.She hardly EVER gets into arguments.She knows how to see both sides and if she can't make peace, she backs off and goes and plays elsewhere.She is the only one in a class of 30 going to grammar, she is not phased and has let the occasional negative comment wash over her.She is easy going but also secure enough not to rise to baiting.
DD1 is more headstrong and had more of the kind of trouble you describe SP ,although the worst of it came from boys.
If DD2 was a boy I would think"boys are so much easier" but because I have all girls, as I said, I think her easy time at school is down to personality type not necessarily gender.
People who have both boys and girls tend to put " differences" down entirely to gender.
Last point - when DD1 was small, she had all the "problems" some associated with boys .She had trouble conforming to "sitting still" and always needed to run and let off steam.She would wriggle and wriggle in church services and generally charge about the house pretending to be a dinosaur.
All behaviour associated with boys.
That was just her being her.Now she is a sophisticated teenager who would not care to be reminded of her dinosaur days.