Even though I love Siri and how you can have quite a bit of fun with it, Google Voice actions are clearly faster.
Motorola pit their devices using Google Voice Actions, against iPhone's Siri. The show off how Google's version of speak recognition is a lot faster and can manipulate Google's amazing built in apps to get things done super quick. You may be able to talk to Siri to have a small conversation or a bit of banter but that novelty wears off quickly. I use Siri to get tasks done and after using Google Voice Action's I've found Google's version is quicker. The only thing I'd say Siri beat Voice Actions at were at reminders and searching for something like "world's tallest building". In Siri it will show the data within the app quite quickly, Google Voice Action's will instead search it in Google and then you will have to click on a link to find the data which is time consuming.