I had An Oscar scan about three weeks ago. It was a blood test plus a nucha scan. It costs about Hk $1600. Test came out about 5 days later and it concluded that I am at low risk ( vs high risk) and no need to have CVS or Amnio test.
Before we decided, My OB explained the options for testing down symptoms to us and we chose Oscar because we thought it's actuate enough yet safe from miscarriage.
I guess it's worthy because it brings peace of mind. I understand some parents would say that they would have the baby no matter what. But my husband and I chose to get to test for it. Our insurance cover 100% but even if it didn't, I think I would have opted for it.
It really depends on what you think of your pregnancy.
Hope this answers your question.