Google has just released its' new voice search features. This is downloaded in the form of an update and is included in the Google Search app. This application provides users with contextual results for voice queries and will answer text input questions using Google.com.
On a side-by-side comparison Google's new voice search returned more accurate results much sooner than Siri. Google is even able to show you results as you are speaking them similar to auto-complete. Siri is not able to show any results until you are done speaking.
Another great thing about this search is that it integrates into existing Google products such as Google Drive and Google Calendar. The Google search app is available to both Android and Iphone users.