From time to time I receive constructive feedback (not the audio kind) about the mix. I'll share with you the most common comments I receive, then why I think it's important to get this right:
1. The lead vocals were not loud enough. "I couldn't hear the melody or what you were saying."
2. The electric guitar was too loud.

I don't receive the complaint that the electric was too loud nearly as much as I hear that the lead vocals were too quiet, but I have received it a few times. The electric guitar is an important part of the mix because it helps define the sound of our modern worship style.

More importantly, it is critical to hear the lead vocals and melody above everything else because that is how people know what to sing. If the melody is low, congregational participation will reflect that. People will be reticent to sing out if they're not sure what the melody is.

So just keep these things in mind when mixing.

PS - I have not received ANY complaints about the overall volume being too loud or too quiet in a long time. Keep up the good work!