There is a comparison table from CPF website.
For Aviva
1) Aviva provide free coverage for children
2) Avia co-insurance is capped at $25,500.This means that if the bill after deductible is 400k,10% would be 40k, but for Aviva is cap at $25,500
3) Aviva policy year limit is higher - $650k
4) Extra 150k/yr for 5 critical illness
5) Interim cover due accident (not sure GE have or not)
For GE
1) The final expenses is higher - $7000
2) The pre/post hospitalization treatment period is slightly longer up to 120 days
3) Insured donating organ, $50k/transplant
Hope that it helps
If you want to know more about Aviva shield plan, you can pm me.