Good one! I've seen some of musicians at the Pentecostal churches -- guitars, drums, organs, fiddles and such. All that's missing is a mechanical bull and it'd be just like going to church at Billy Bob's! And I do mean that with good-natured humor since my intent is not to mock those worshiping differently. We in the coC get plenty of ridicule for the way we do things.
I’ve started to go to a Baptist church that has, well, everything shy of the mechanical bull. The worship leader even has a standing keyboard, which is new to me. And so what, as long as the ultimate focus is upon Whom it belongs (and the music is competent). If you sense a spiritual benefit from a-capella musical worship, then more Power to you. In most places, the keyboards are a great help. (Don’t be shot by the piano player!)