Back in the 70's I was educated in Australia for my Primary learning and was amazed at certain things that kids in the UK were behind on such as writing, reading and times tables.
I must admit that having put my two through their primary education in the UK I feel it is substandard to what I received at Christies Beach Primary School back in the 70's. Having said that I do think kids develop at their own pace and they understand things at different times - this has nothing to do with where they are educated but just them.
Personally, I would rather all kids came out with at least an average education but more importantly a well rounded individual who has achieved their best, has manners and tolerant of all kinds of people. Qualifications are not the be all and end all to education and parents have a massive role to play in a childs education in everything.