I'm also in the search process and have learned a lot (about those two agencies and many others) from both the general Adoption Agency Research group on Yahoo and the Ethiopia-specific one. CHSFS also has their own discussion board you can browse to see what the experience is like for their clients.
General agency research:
Adoption_Agency_Research : The Adoption Agency Research Group
Ethiopia agency research:
EthiopiaAAR : Ethiopian Adoption Agency Review
CHSFS:
Ethiopia -
Good luck,
Shelley