Many performers that use headset mics prefer one that is nearly invisible called the "countryman"
Avoid the old black ball "madonna type" mics. They look old and distracting.
Some still prefer a basic mic stand and mic, which gives them the ability to remove the mic and walk around, or keep it on the stand when they are using both hands.
Also there are the "gim-crack" portable mic holders which I really dislike but some still use them. They look big and are clunky and you drag the wire around with you, but it does leave your hands free. It puts a standard mic into a neck holder and keeps it in front of you. http://themagicwarehouse.com/TA6290/Gim-Crack-Microphone-Holder.html
Obviously the advantage of a headset mic is that it is "always" in front of your mouth, so you never go off mic when you turn your head. The mic on a stand, the lavaliere or clip on mic, and the gim-crack allow you to turn your head to cough, or to whisper if needed to your audience volunteer, etc.
Pros and cons. I'm sure others will chime in too.