Cinder's feature set is highly optimized for IO bound web services that run under a forked-worker model.

For example: you start a main process, warm it up with a few requests, run the JIT compiler and then fork off worker processes to handle the main chunk of traffic.

As of now, it requires hand-tuning to get the best possible performance.

In terms of use cases, Cinder does the best when faced with "business logic" code (lots of inheritance, attribute lookups, method calls, etc). It can speed up numerical computations too, but you're probably better off using a library if that's the majority of the workload.