Voltor Longo mentioned this new work as being very promising so it likely is a better way to measure biological age. Personally I haven't taken any such test because I haven't found one good and affordable enough - if this gets commercialized it might be the ticket.
OTOH while my health is better than when I was 20, do I really want to know what the biology says? All tests are subject to error, and I don't do measurements unless I know how to mitigate a negative result. I can't do anything beyond what I'm already doing for health, so there's not much point, unless the number comes out fantastic (which I guess it probably would honestly) which would have positive psychological benefits.