Has anyone gone any experience of using Neo4j with terabyte sized datasets? I would like to hear about your expereinces with how Neo4j performs
As long as your disk is large and fast enough and your memory allows for caching of the relevant (hot) portion of your data, you shouldn't run into issues.
There are optimizations for tuning the Neo4j datastore to specific needs.
Otherwise it depends on the kind of your dataset. Query performance shouldn't be an issue, insert performance might suffer if you have to do a lot of index lookups for joining imported nodes (But the Neo4j team works on that).
Perhaps you should join the Neo4j mailing list to answer all your questions more consistently.