We know Google demotes non mobile friendly web sites in smartphone search results. But for some reason, there is a debate if Google gives a ranking boost to responsive design sites over other mobile formatted sites that deploy Google's best practices.
The truth is, we covered this before, Google has said responsive design doesn't give you a ranking boost. Of course, having the same URL does help with links, there are less technical issues with responsive design, etc. But Google does not give a ranking boost for going responsive versus other methods.
Google's John Mueller confirmed this on a video at 5.5 minutes in:
Q) Does responsive designl rank better than other two formats Google recommends?
A) That is not true.
So there you have it.
Forum discussion at Google+.