What is your favorite RDF triplestore?

I am able to convert numerous library-related metadata formats into RDF/XML. In a minimal way, I can then contribute to the Semantic Web by simply putting the resulting files on an HTTP file system. But if I were to import my RDF/XML into a triplestore, then I could do a lot more. Jena seems like a good option. So does Openlink Virtuoso. 

What experience do y'all have with these tools, and do you know how to import RDF/XML into them?

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Eric Lease Morgan