Choosing an a voice solution

...actually needs a voice solution.
Most solutions seem to work well. I would look at cost/benefit and put it in terms that the directors or management understands. Give your management three solutions - a Gold, Silver, and Bronze solutions and let them choose. At least if they choose the Silver solution and it fails to meet expectations you can always point out the fact that you offered a Gold solution. Now if they chose the Gold and it screwed up...

Your organization's business requirements would be a good starting place. Although it's not clear whether you need an IVR or a voicemail system, the issues are pretty much the same -- what you hope to accomplish with it, transaction volume, scalability, reliability, vendor reputation, hardware requirements, cost, maintenance, and of course, ease of use.

Good luck.

Craig Herberg