Selected answers from the Dumb SEO Questions G+ community.
JL Faverio: I`m really a fan of no slideshows for SEO. I recommend making your opening page a clear call to action, make it relevant and ensure the hero image is optimized to load fast. and if it doesn`t look good on mobile, display:none it.
Dave Collins: Assuming you use a reasonable solution, there shouldn`t be an SEO impact. But it depends on how they`re created. The bigger question, in my opinion, is whether you want to give up control over what your visitors see and when they see it? I think they`ve had their day - for most websites anyway.