Barth is the big dog for mainline evangelicals. Take that for what it means.
He has some good things to say: he stood up to the Nazis and radical Liberals and he stood for the basics of our faith. He compromises/muddies the doctrines of Scripture and election. He taught that the Bible is not God's Word, as Jesus was. He also taught that inerrancy was for fools and that historical criticism is valid. He also was fond of overly long-winded sentences that are almost unreadable.
Just get a guide to his thought if you're interested. There are several smaller works available.
Now, paging Grymir.....