Lightning is a distribution of Drupal 8 developed by Acquia which attempts to deliver a preconfigured and optimized out-of-the box experience.
The installation via Composer is smooth and setting up the site with the default profile is all that is necessary. Nice.
You get a site which provides you with Panels via Panelizer, Media management via media and entity browser as well as moderation via Scheduled Content and Workbench Moderation.
On the other hand, I'm surprised not to see Paragraphs here and the reliance of media embedding in rich-text components seems inelegant. Also power-user essentials, such as Admin Toolbar, are lacking.
Lightning provides a very nice showcase on how you can easily upload and reuse assets with the entity browser.
I look forward to using that in future projects, though its still odd that there is barely any documentation on organizing or segmenting asset management there.
Apparently, Views will need to fill that gap, but I hope future improvements here will set a greater focus on image pools, as easily accessible as now but with more fine-grained controls, when you can't trust your editors to do the right thing.
Until the 8.2 merge of Workbench moderation as "Content Moderation" I was not certain which access control suite might come out on top for 8 but Lightning seems to have had the right idea.
What is surprising is that the experience of scheduled content is rather grim in terms of workflow states and publishing processes. The user does not have any good feedback what version is currently published, how to go about modifying them, nor do additional pending states seem to work at all out of the box. That needs lots of work and is a major weak point compared to the usual enterprise CMS offerings, which I had hoped Lightning would have a better answer to.
Lightning is a great demo case to show how Drupal 8 is in many ways a different ecosystem than 7 and what it can do but I would not necessarily choose it as a base distribution since it's not hard to take a look at their example and tailor your site to your actual needs.