BagCheck Separates Mobile and Desktop.
A common sense explanation from Luke Wroblewski on why BagCheck doesn’t try to serve a single HTML page to both mobile and desktop users:
A desire to optimize source order, media, URL structure, and application designs made separate mobile and desktop templates a great fit for us.
Responsive web design isn’t a panacea, and to be clear, nobody who understands it is promoting is as such. Yet there seems to be a disproportionate amount of hype relative to its advantages. Can you provide a marginally better experience at different browser resolutions using the responsive web design principles? Yep. Should you solve every problem at the CSS level? Absolutely not. We have a lot of tools including HTML, JavaScript, and server languages available to us to accommodate the radically different ways people interact with our content and applications. We should use whatever best suits the situation. That’s not a particularly bold or esoteric statement, but it bears repeating from time to time.