I'm having issues with captions, and I'm not sure how much is WordPress and how much is Supersized.
Using apostrophe (') in captions will make the slideshow display the loading graphic indefinitely. WordPress has issues with the symbol, but AFAICS captions should "just" be truncated - here the slides just don't load.
Secondly, a linebreak in the caption (simply pressing enter, no code) will also break the slideshow and cause it to not load. It's not a huge issue, but for users of the site (i.e. the clients) it's just yet another thing they have to remember not to do or their site will break.
Other than that, it's a fantastic plugin. Thanks for the hard work. :)