We have a strong focus on provenance, Tribuo models capture their input and output domains, along with the necessary configuration to rebuild a model. Tribuo's also more object oriented, nothing returns a bare float or int, you always get a strongly typed prediction object back which you can use without looking things up. Tribuo is also happy to integrate with other ML libraries on the JVM like TensorFlow and XGBoost, providing the same provenance/tracking benefits as standard Tribuo models, and we contribute fixes back to those projects to help support the ecosystem. Plus we can load models trained in Python via ONNX.

To your direct question, I've not benchmarked Smile against Tribuo. We are very interested in the upcoming Java Vector API - https://openjdk.java.net/jeps/338 - targeted at Java 16, which will let us accelerate computations which C2 or Graal don't autovectorise.