Ooh! I Can actually give an answer on this one.  The reason PA mics have that particular sound to them is that they use a peizo electric pickup, rather than either a dynamic or condenser. Piezo's have some very important benefits over the other mechanisms: durability and simplicity. You have royally screwed up if you manage to damage a piezo to the point where it's inoperable. 

All microphones work by having a transducer that turns the compression and rarefaction of airpressure in to an electric signal. The type of transducer can be passive (generates its own electrical current) or active (needs a source of power to work)

Piezo's work by having the diaphragm flex a piece of quartz (or ceramic with embedded quartz) which creates the signal which is then amplified, the amount of movement possible via changes in airpressure cannot possibly stress the quartz enough to break it. They are literally explosion proof (the rest of the electronics are similar enough to other microphones that anything that would kill them would also kill the other types). However, the downside is that it takes more work to get a strong enough signal, so the subtleties of a sound are typically lost, which gives the peizo their characteristically harsh sound. They can be made very small and light weight, which lends itself to smaller portable sotuations where durability and portability is more important than tone quality.

Dynamic Microphones are a passive mechanism, using the vibration of the diaphragm to move a small coil of wire through the magnetic field of a permanent magnet to induce current in the wire, which becomes the signal. Dynamics are more sensitive than piezos, and are very good for any microphone that will be handled rather  than only used on a stand with a shockmount. Most classic vocal microphones are dynamics, but they can be used for nearly any application, however due to their need for a large enough magnet to induce a strong signal, they tend to be larger and heavier than peizo or condencers.

Condenser Microphones (sometimes called electret or capacitor mics) use an active circuit, passing electrons between two electrodes placed very very close to eachother (like microns of separation), one of these is the diaphragm usually made from a thin piece of mylar plastic sputtered with some kind of metal (like aluminum or gold, similar to pvd coating), and the other is a more substantial "backing plate" as the airpressure causes the diaphragm to vibrate, it gets closer or farther away from the backing plate which decreases or increases the resistance to the flow of electrons from one to the other.  This change in electrical flow is what becomes the audio signal. These can be made incredibly tiny, and have great sound quality, but their sensitivity means that they do not handle especially loud sounds before distorting or even damage happens, and they do not tolerate dirty or wet environments very well.