The PCC160 and the 170 are very close in performance to each other except for the body of the microphones.
The PCC-160 has an all metal body making it great for the front of a stage were it might get stepped on. As a matter of fact I used to do a demo where I would balance on one foot bouncing on the PCC-160 and then plug it in and talk to it. If you did that with the PCC-170 you would crush the microphone. It was made for to be a little smaller and more decorative for use were the PCC160 might not need to be as ruggedized-like on board room conference tables, lecterns and alters.
Either microphone would work well on the front of the stage for stage micing depending on if you can keep people from accidentally stepping on them.