I've tried quite a few sliders in different projects, but I must say that Smart Slider 2 is by far the best. On one hand you have an integration with all the popular content providers (including e-commerce!) and on the other a fully customizable, powerful, sleek and visually stunning presentation. Lots of integrated layouts, support for html, video, iframes and more on slides, layers with parallax effects and pre-built animations. And all this wrapped in a great backend control panel. You just can't go wrong with this one.
And I haven't even mention support yet. It's fast, effective and professional.
5 stars and my slider of choice.