I've switched from Solr to ElasticSearch. They're very similar, but ES is easier to maintain and has some nice additional features. They are both based on Lucene and are both fantastic projects.
I find it hard to believe that there are many devs out there who are interested in search yet have never heard of Solr.
You can be interested in open source and not know about it. (Especially if you're thinking, "Wait, _this_ is one of the most in-demand skills?! Maybe I should find out about it!")
You'd be surprised then. I'm not sure why, but I know lots of developers who should know about Solr but haven't a clue. Hopefully they will now.