What can I learn from them?

When you listen to some teachers or preachers it would appear that if we didn't believe exactly what they believe then we are a heretic. Well that may be true but it is also a very dangerous position. As a Christian I hope I believe all the right things but I am not so naive as to think that all my theology is right. As a Calvinist I can learn from an Armenian; as a pre-mill I can learn from the a-mills. We have to be careful that we base our beliefs on the Word of God and not upon man's teaching. We can learn a lot from other teachers but we must also keep in mind that they are not God and we must not treat them like God.
Paul reminds the Corinthians that different leaders have different responsibilities. That does not make the one who plants greater than the one who waters or even the one who harvests. Until we realize that all these teachers are a gift from God we will not be mature in our Christian faith.