Google has stated multiple times that responsive design is their preferred mobile configuration, leading many to speculate that responsive sites might get a rankings boost.
Responsive design approach uses fluid, proportion-based grids, flexible images and varying CSS style rules to deliver different user experiences to desktop, tablet and mobile devices while maintaining the same HTML and URL structure. The site shrinks or grows according to device.
Google has been nice enough to outline the pros and cons of each design choice in their Mobile SEO Guide’s Responsive Web Design
The responsive Web design page distinctly says,
“We [Google] recommend using responsive web design because…” and then goes on to list six ways responsive design saves Google resources, delivers improved user experiences and avoids SEO pitfalls.
This is an easy one, because it is clearly specified by Google & is better for your users as well.
Quite simply , it has to be done