I presented at the Lucene/Solr Revolution 2014 in November, comparing Solr and Elasticsearch. The target audience was a technical person who wants to understand how similar (mostly Lucene) concepts are expressed in these two products.
The presentation was only 30 minutes, so I could not go into the subject as deep as I initially hoped. But the room was more than full and people came up to me afterwards saying that they really liked the comparison and found it helpful.
The slides are available already and the video should hopefully be out soon as well.