currently i evaluate Mantra and found this bad issue:
if enabling the responsible option, it also disables the possibility, to zoom parts of the pages with ipad gestures (pinch-to-zoom). lots of people want to read the pages without their glasses, so they use the zoom gesture to better read text and photos. because this doesn’t work any more if setting Mantra’s option to responsible=yes, i need to disable it.
I think, the best would be to have an option to enable/disable the zoom possibility.
Also a good idea would be to enable gestures to switch slides of the slider.
more info about this common issue you will find here:
http://ux.stackexchange.com/questions/37511/should-users-be-able-to-zoom-in-a-responsive-webdesign