I was a late convert to responsive, I kind of came down the path of build a separate mobile site as everyone was thinking that the web was going to be supplanted by the mobile web but that did not happen, what happened was that people are using everything to access the web, and the list of devices are growing after doing a few responsive site I can say that I am sold. It is the only way that I can see that we can support the array of devices coming online with a single integrated solution.