PCX vs. JPEG

I work in a company where we help other companies, law firms etc with presentations. For many of our graphic needs we use PCX files. I understand on a very basic level the difference between these file types, but I have been assigned the task of exploring the benefits of one over the other. If you know, I would love to hear from you. If you can point me to a resource where I can learn this I would appreciate that as well. Any help is appreciated.
Thanks,
Rosstamon