both my ds's haven't had problems at school going from yr2 to yr3 BUT they have both changed in their behaviour at home..for the worse. They both seemed to suddenly start pushing it again, and mouthing back at me and occasionally dh as well. They seem to be beginning to morph into Kevin and Perry at times as well.
It was a big change for my DD as they go into a different part of school for Juniors.
I was quite confident as DD is fairly laidback, however she has found it really hard. For example there was a significant step-up in homework and they appear in my DDs school (state) to have whole weeks every so often of just testing and then they give the children (not parents) a re-assessment of the SATs mark they achieved in Yr2.
On the plus side, they do projects and swimming lessons. She loves both.
All of this I guess may differ from school to school.