Hey buckwheat,
Good question. This is best answered by your situation. The supervisor itself works perfectly normally with other processes around it. That said, normally we do not recommend running the supervisor on the same machine as that of a worker. This is because renderers especially those used on film projects tend to grab all of the available ram and end up starving out other processes (thrashing). Because of this, the supervisor daemon may be forced to shut down or will be significantly less responsive.
In practice, it is better to use a slower machine (one which can't do rendering anyway...) as the supervisor rather than have it share a single fast machine with a rendering process on it. We typically test the supervisor's performance in running a farm larger than the one you have mentioned using a 550 Mhz PIII w/ 512 mb of ram. You'll also find it easier to perform supervisor maintenence and can more easily control physical access to the host to prevent users from granting themselves access beyond that approved by the administrator.
Beyond this recommendation, the Supervisor itself is ok with co-existing with other applications.
Thanks,
Anthony - Pipelinefx L.L.C. Support