I'm ambivalent though - I'm happy to reverse the change to the example solrconfig.xml too, though I like that one can fire up the example configuration with a different data directory easily.
I am happy either way - relative to solr home or just commented out.In this case, relative to solr.home makes the most sense. I like -Dsolr.data.dir=XXX out of the box, but enabling it explicitly isn't hard...
