I voted "yell?" but to be honest, I alternate between shouting into the microphone and pressing the button.
Speciffic points, since I end up pressing alot. I normaly use the button to press a witness.
On the other hand, Objecting is when I use the microphone. The reason is simple, it's fun to shout "objection!"!
I also shout into the microphone for the command "Take that!"...
** Spoiler Alert!!! click to hide or show**
and the Gyakuten Saiban 4 command "Got'cha!"
My main point, include a third option that says "both?"
Edit: Now that I have the English version of Gyakuten Kenji, I also use the microphone for "Eureka!".