hehe yes the play button is nice to press, I'm glad I got a membrane button as the tactile feedback is much better. You can really feel it clicking and its sealed so when you sweat all over it, it dosen't short on ya.
Also, here's a video of a performance using the button_box. The heavy sine wave at the beginning is the loading tone and you can see me press it. It's easy and dosen't slow down the action ... it's also cheaper then having an extra person to work the computer 
That bright red light is the button_box velcro-ed to my chest.