The one thing that always come to mind with responsiveness is that the more complex the site, the more difficult it is to make responsive web work. Now this may sound intuitive, but I am always astounded as to how people now think that responsive web is the magic bullet to solve all woes.
I think responsive Web is really at its most powerful if the site is minimal (like google). For any advanced site, either lots of care needs to be taken or perhaps the dreaded "m" subdomain?
You can have your cake and eat it too if you focus on client-side adaptation. For instance, with MIT-licensed Mobify.js which we recently released (http://mobifyjs.com) you can have any amount of mobile-specific functionality while keeping the URL of your desktop site intact. Works especially well if your site is complex!
I think responsive Web is really at its most powerful if the site is minimal (like google). For any advanced site, either lots of care needs to be taken or perhaps the dreaded "m" subdomain?