A lot of people, myself included, talk about responsive design. Even this site uses responsive design. (Don’t believe, resize your browser’s width and see for yourself.) Responsive design is a good thing for web design – and CSS makes it possible.
However, it isn’t perfect. So read the article to see why you can’t expect responsive design to be exactly the same on every device, save development time, or even load faster. However, even with those things in consideration – you have to look to see if it is good enough for what you want it to do.