Soliloquy
Soliloquy is a really great slider, with tons of features. It is well-built, robust, and is the fastest loading winner when compared with 5 other sliders. It's mobile-optimized.
*Uses images 500 x 600px (optimized)
Soliloquy Carousel
Here is the Soliloquy slider with the Carousel, Lightbox, and Thumbnail features enabled. The Carousel works well. The thumbnails do not appear as steady as Slider Pro and they seem to "glitch out" below some of the time. The lightbox, if we do say so, looks almost identical to Slider Pro. Did someone borrow someone's design? Perhaps. Since both of these are GPL software, this could be the case.
Soliloquy Image Slider Verdict
Soliloquy works quite well. It's obviously well designed for the most part. It's mobile friendly, and the lightbox and thumbnails seems to work well. Not sure about the thumbnails above, which have glitched out a few times. Perhaps too many sliders on one page for Soliloquy's liking? For the carousel, there is a setting for number of slides to scroll. I would like to be able to set this independently for the mobile and non-mobile displays. Why? In the non-mobile, I may want to present 3 slides at once, and then scroll by 3. But on the mobile, I would only be able to accommodate 1 slide in the viewport at a time. Obviously, I don't wan to scroll by 3 slides in that case. Soliloquy is a very good slider. Another nice to have would a slide preview feature. It would be a great addition!