Zivush - 6:01 pm on Mar 20, 2013 (gmt 0)

Thanks for the responses.
Since site's overall performance must impact ranking, RWD may have an indirect positive effect on ranking (if it hasn't have any direct effect).
@netmeg
Have you taken care to serve the appropriate size of ads on every screen size or you just left the ads of the wide screen version?
Our sites also see millions of visits per month where many of them are from mobile devices.
Thanks for your tip. The very basic reason for switching to RWD is our eCommerce sites.
@canuckseo
I agree with you.
Responsive layout is the future. No doubt about that. Our sites are Wordpress sites too, but the original theme we use wasn't responsive. Now it is. It took us ~ 3 days to get the idea of responsive design and 3 days more to implement. It's a way better design approach. Very flexible.

I still can't ignore the risk of switching to a new design. It exists, but we will do it even if Google screams. That's how we always work.