Our DS did IGCE's on the whole. Very similar to the old O'level - exam based and more rigorous than I remember my O'Levels. DD doing similar. We are very pleased with that decision and relieved they are in the independent sector.
I don't know why people are concerned that returning to the old format O'Level will reintroduce two tiers. We have that already with NVQs and Level I, II and III qualifications. Hopefully this change will introduce rigour for the bright and more work based qualifications for those who lean towards more vocational subjects.
Hopeful that increased rigour will mean that there will be greater emphasis at primary level to achieve acceptable standards of literacy and numeracy.
Finally, surely it's more motivating to get a good mark in a more vocational tier than it is to get a very low graded GCSE that counts for nothing.
In a few years we might even realise that we need smaller schools and more differentiation because adults, men, women, children, teenagers are all different and one size doesn't fit all and can't meet the needs of all.