Pump Gags

I love the idea of a pump gag, but have never tried one. I'm wondering what they are like, so I have a few questions to anyone who has worn one. How well do they hold the air pressure? Are they more comfortable than a ball? How well do they muffle? Is the bulb a serious distraction?

I haven't worn one but...

Yes, the well made ones hold air quite nicely.
No, they're not "more comfortable", they're meant to be invasive. They're meant to simulate a cock going down your throat. Meant to (imo) humilate or degrade.