This is not a slam against the developer. Don't take it that way. But I tried the plugin in over 15 different themes, half responsive and half not, and never got it to work as shown in the demo, except for in the twenty-twelve theme - which is responsive. Aside from the menu and right column layout issue (which I do undersand is a css issue on my part) the entire sidebar disappears when expanding a product. When expanding a product info, the menu is no where to be found and a bunch of random text shows up. I tried this on three separate installations of wordpress.
I am not upset (I did not pay for this plugin) but was really wanting to use it. I just thought it would work more'out-of-the-box' as displayed on the demo site.
Like I said though, this is not a shot at the developer. The support and email responses were great, and too me, I appreciate that way more. A+ for support! :) The true problem with my experience is my non-ability to style it with css.