Muhammad Ibn Haaroon Al-Fallaas (rahimahullaah) said: If you see a man speaking ill of Yahyah Bin Ma’een, then know that he is a liar who fabricates hadeeth. He only hates him (i.e. hates Yahyah) because of what he clarifies concerning the affair of the liars.
Question to Al-Allaamah, Shaikh Saaleh Al-Luhaydaan (may Allaah preserve him):
”Why is there so much speech about Shaikh Rabee (may Allaah preserve him) and why do they speak ill of him?”
How excellent a man he is in his creed and jealousy for the Sunnah! And there is no doubt that those who speak against him do so because he refutes those who oppose the Sunnah. They hate him because he refutes the Mukhaalifoon (i.e. opposers of the Sunnah and the sound methodology of Ahlus Sunnah). And perhaps the one who does not oppose (the Sunnah) envies him because he cautions against what that person does not realize. How excellent a man in knowledge and religion! 
 [(تهذيب الكمال(20/220)]
[slightly paraphrased… Download audio here: http://www.sahab.net/forums/index.php?showtopic=141370]