My Grandfather was a missionary in India back in the days before independence. He would treck around the place taking services and preaching. In some of the churches he went to they might not have a pianist able to lead the singing, in which case he would do double duty and play the piano as well. After one particular service a lady approached my grandad and said, "well, I guess it is better to have bad music than no music at all!" My grandfather never played the piano again.
Apart from being a salutary lesson about the power of unkind comments I also think the lady's statement was somehow missing the point completely. CS Lewis remarks in God in the Dock (p61-2) that when he became a Christian he was at first appalled by the "sixth rate" music and terrible singing that he found in churches. He soon worked out though that the point of the music wasn't whether or not it was good, but whether or not it was being used for true devotion towards God.
In this way it is in fact better to have bad music than good music in church. When the music is good, you might be mistaken into thinking that you were there to enjoy the music, or that the music was somehow the point of the exercise, or even that the music was glorifying God on your behalf. When it is bad there can be no mistaking that those who join in are more concerned with worshipping God than enjoying music.
The popular notion that churches with great music will atract people is of course true, they will attract people towards music. Churches with great devotion to God, however, will attract people to devotion to God.
Of course all this comes undone when the bad music is actually the result of the musicians picking inappropriate songs, not rehearsing properly, not bothering to learn their instruments to an adequate standard, or general laziness. The attitude of 'it's only church' is as antithetical to worship as the attitude 'the music must be perfect.'
Sometimes I dream of a church without music...