They are both good..

It totally depends on the desired goals of the project..

I am working on home automation, but the goal is total voice command when home from any room without having to pick up a device..

So, raspberry pi for the controller, and right now probably the data collectors. Then

one of these for processing the voice

http://adapteva.com/docs/e64g401_datashe...

Then off to home genies's api and finally a zwave hub to get / control the state of the end points..

Personally I like Arduino better, but Raspberry Pi is a more than adequate substitute. We use both at our 3D printing camp at FIT in a few weeks.