The church I attend on and off is tax-exempt. I don't know too much about it, but when my dad attended their he handled their finances. However I do know that it was because it was a non-profit organization.
Now to answer this question, do I think they should be tax exempt? I'm kind of caught in the middle.
Some churches are for profit. I think they also take advantage of being tax-exempt. They're like a big business. The preacher is the wealthiest one in the church with his fancy clothes, brand new cars, huge house. I wouldn't even call these places a "church". They take advantage of the people in attendance. But it would be kind of hard to make these places pay taxes based on that.
I hope that makes sense.