Best Outbound Solution

Hello,
I am interested in knowing what other customers see as the ideal Genesys Outbound Solution.
We have 3 options:

  1. Outbound VOIP (SIP/VOIP) - this is taught in their classroom courses
  2. SIP/GVP/CPD with Dialogic HMP - Is also including as a chapter within the course manual but not actively taught.
  3. SIP/GVP/CPD with Sangoma - not taught in the course but supposedly most compliant.

Which one would you use?

Thanks,WA