hi Col, I'm Looking forward to hearing how the Shure WH20XLR sounds and works out for you live on stage.
It certainly is a lot more affordable than the Crown CM311A.

My main concern has always been the issue of a headset mic's "fixed proximity" to your mouth,
and the challenge of recreating the trad mic effect of "pulling away" from or coming in close to "kissing" the mic.
Do you lose these effects altogether with a headset mic or are there specific headset mic workaround techiniques to recreate it?
I also assume that headset mics all include a convenient remote mute switch switch for when you need to cough or clear your throat.

Scott