Phone Answering Service Recommendations?

Does anyone have success stories/recommendations for phone answering services? I am looking for something that will do the following:

  • 24/7 live operator answering.
  • Gather basic information about the issue/problem.
  • Call the scheduled “on call” person to pass the info on to.
  • Call the next person on the schedule list if the first, second, etc. is not available.
  • Email the information gathered from the caller to the “on-call” person who is reached by phone.

I’ve found lots of results but few recommendations that I feel comfortable with.