Responsive Design vs Mobile plugin for Wordpress?

Which do you guys think is the better solution as far as performance and branding is concerned?

I've heard some people say that responsive design can have a slower performance on mobile phones as apposed to using a mobile plugin solution.

But I've also read that responsive design is far better in terms of branding?

What do you guys feel is the best way to go?

branding, speed etc. responsive is the way to do. I different theme for mobile users brings along a lot of hassle

I think more plugins more slower.
RWD is good solution for mobile