Hi HH,
I think your DS will enjoy the test as long as he feels there is no pressure. That is exactly what we did with DD. She kept saying she didn't know if she wanted to change schools and was very ambivalent but once she changed it became clear how truly miserable she had been in grade four.
Was the teaching different? It was but as I said, it was very much down to the individual teacher. DD had a teacher who was able to take them to a higher level in most subjects and then supplemented with online learning, eg in maths using maths on line for teaching algebra. The other OC teacher was more academically driven from what I understand, where DDs teacher encouraged art, musical pursuits and sport to a greater degree.
Homework was a big difference with much greater workload and much higher standard. There were essays to write, dioramas to build, science experiments to construct and write up with excel graphs. DD even wrote a book one term. I felt the pressure at times but in reality the teacher was stretching the kids and it isn't like they would "fail" if they struggled. Most of the OC kids found high school and homework a breeze after the OC preparation.
Regarding selective schools, I just don't think our DD would have been happy with the workload. It depends on the balance between the amount of work versus the level of work and the pacing. However, we didn't investigate it too deeply as the travel needed to attend a selective school was prohibitive. DD wouldn't have had time or the energy to attend other external activities she enjoys.
Let me know how you get on with investigating the OC and feel free to ask any specific questions if I can help
