Paul writes to the Corinthians: Whatever I am now, it is all because God poured out His special favor on me...It makes no difference whether I preach, or they preach. The important thing is that you believed what we preached to you.
Listen to lots of good preachers and you will hear truth from lots of different voices. All of whom are speaking by God's Grace, of God's Grace.
Just a reminder to us preachers that we are interchangable, the important thing is the Word, and the reception, not the preacher!