Rogers 4000 or Duroid?

Hi,

I am just wondering, is there a special reason (other than the different dielectric constants) why a circuit designer would prefer to choose Rogers 4000 series rather than Duroid based materials? I am asking because they both seem to work well at high frequencies, hence wondering what gives one an edge over the other.

Thanks
Fendi

Cannot ignore the dielectric constant which is important at microwave frequencies where these materials are used.

Duroid has lower insertion loss at microwave frequencies (10 to 18GHz).
RO4000 is cheaper.