Well, that depends. If you run a small departemental cluster where all the users can agree among themselves when and where to run their jobs, you probably don't need a queueing system at all. But, if you have too few machines and users start stepping on each others feet you definitely need one.
How does Torque compare to SGE? Don't know, I've never tried SGE, go figure out yourself what you like best. Torque (or rather PBS) and Maui has been around for a long time and has a lot of features that come in handy when you try to keep your users satisfied sustaining a reasonable job throughput.