Been thinking a lot on this and my conclusion is:
Responsive Design + separate site
I believe that if I give an user (for testing purposes) one website for viewing on a mobile device, and a responsive website to try on the same device... the user will go for the responsive one being easily readable.
What if we give the user a third option? a mobile website? and let the user choose between mobile and responsive? the mobile site will load faster, ready for trying while the responsive will not (in most cases). That's my bet. I was doing experiments with one of my sites (the one with more traffic) and [RD] responsive design, I finished and was actually bored, I wasted a lot of time there due to the device limitations (Android phone and Android Tablet on a fast internet connection). Well the finalized mobile version loads in a blink of the eye.
Jquery is the solution for some cases, or so it seems, but many devices won't be able of even running the tricks. We all could disagree here because our opinions will be based specially on what devices we use to test the websites, but that doesn't mean most people have Iphones or fast Android Phones/Tablets.
A practical website should be able of showing the user the right version for the device and screen. Not easy, but speed wins I believe.