I was pretty impressed when my MagicJack sent me my phone message to my email, just audio though, no transcription.
One thing that has changed in recent past is that the cost has come down significantly, making voice apps accessible to smaller developers and hobbyists.
For those that want to use Asterisk and still take advantage of a web-centric programming model. Take a look at Adhearsion. It's an open source Ruby framework for writing Asterisk apps. Voxeo is a current sponsor of the project. http://adhearsion.com/
We do plan on implementing the Adhearsion API on Tropo, allowing someone to build a portable app that runs either on their own Asterisk server or on the Tropo cloud.