I noticed the following tabulation on your repo’s home page.
| Database | Status | Strengths |
|---|---|---|
| Blazegraph |  Working |
High performance, easy setup |
| Apache Jena | Working |
Robust, standards compliant |
| QLever | Working |
Extremely fast queries |
| GraphDB |  Planned |
Enterprise features, reasoning |
| Virtuoso | In Progress |
Mature, SQL integration |
| Stardog | Planned |
Knowledge graphs, reasoning |
| Oxigraph | Planned |
Rust-based, embedded |
Regarding Virtuoso, its differentiators are as follows (in addition to obvious maturity):
- High-performance and scalability for SQL & SPARQL – which extends to reasoning and inference plus fine-grained attribute-based access controls
- Ability to use SPARQL via SQL thereby bringing SPARQL to existing SQL apps and services