I use it as a session store for a computer music system. It has worked well for me as a way to read mutable (by any client) parameters during synthesis, clients will often read dozens of parameters during a block of computation (a relatively short window of time in the low milliseconds typically) without adding any noticeable overhead to the render time for each block.

Edit: I also tried using it for larger blobs of data (like audio) but ended up only storing a reference to shared memory for larger blocks, anything larger than IIRC 4k that can't be stored in a single node kills performance, but for small values it seems pretty great.