No ads on the overseas website or on the survey. So, it looks very legit. I read it every day because it has new content from expats and contributors in those countries with their actual names!
And Sixty & Me is very respected.
When something sounds too good to be true, it probably is, and the grass is always seems greener on the other side.
I think people forget how good it still can be in the US, and they tend to overlook problems in other countries. The cost of living is lower there for a reason.