I really nice feature Switchvox has it's the option to query external XML data in a IVR. For example you want to create a IVR menu that reads the balance of your bank account (after logged in using an account id and PIN)
You have the possibility to read XML data from a URL Where you can add variables that is available in Switchvox (standard asterisk like CallerID, Extension etc as well as IRV response (digits etc)
The XML data is put into variables to that will be available in the IVR, for example text-to-speetch. Really powerful.
Would like to see that functionality in Thirdline to :)