Asterisk Vs Genesys

I am trying to find feature differences between Asterisk IVR and Genesys IVR (GVP)

I am using GVP right now but looking for a more economical alternative.

Couldnt find any comparison charts on the web. Can anyone point me to any web link which lists such a comparison (maybe not with Genesys but with other products - or just a plain vanilla feature list of Asterisk IVR? )

thanks ,