> Physical mute button with red LED mute status is a killer feature.
I had a headset with that feature, and sure enough, it failed me on a sales call. I groaned at something our salesperson said, and despite the button having been pressed and the light being on, everyone heard me.
As someone who recently forgot they were still sharing their screen while simultaneously starting to chat with a colleague about how incompetent the person currently talking is... I feel your particular kind of pain.
Physical mute switches can be worse for other listeners as it creates an audible pop every time you mute and unmute on a 3.5mm connection. Digital (USB) mute switches are better.
Analog microphone audio is one wire (and ground) having the AC signal of the audio, superimposed on a DC signal powering microphone capsula. The simplest way of making a killswitch is to either 1) short the signal to ground or 2) cut the signal between mic capsula and the soundcard input. Done with just a switch, both of these will impact the AC component as well as the DC component, and the DC offset change that causes the pop.
And yes, there are many ways to avoid this problem. I think adding a resistor and capacitor to form a high-pass filter for the shorting option would work fine. If there is already a PCB for the switch, adding these two components would cost practically nothing.
The "pop-less" microphone switch is generally a series R-C pair, where the R is, say, 1 MOhm, and the C a few µF. The switch shorts the R out; the R charges the capacitor to the bias level when unmuted, and so shorting the R produces very little pop. The capacitor then shorts the AC audio component.
XLR switches are easier, just short hot and cold, done. Works with all microphones and doesn't produce a pop, because XLR uses phantom power instead of T-power.
The best system for me is the one on the Sennheisser Game One I have and probably many others.
There is a microswitch in the mic boom, so that it is disconnected when you lift it away. I mean, you can't get more simple: when it is in front of your mouth, it is on, when it isn't, it is off. No need for a LED. Also, the headset is passive, with a good old jack connector, I consider it a plus.
My Sennheiser PC37X (their conservative/stealth-looking gaming headset) has the lift-to-mute. I was excited about this feature but struggled to remember to unmute myself and gave up using it. I would like an LED indicator somewhere.
Got a wired Plantronics headset with USB-C that I'm happy with. Not sure if the above products have this feature, but I recommend checking for it.