I almost always prefer the first version I hear of a song to any later versions. Obviously, many covers of classic songs are pale imitations of the original greats, but this extends even to different versions of a song by the same artist. Once that first version clicks on my mind, I either get into its groove or I don’t. And any subsequent version will be judged on how I reacted to the original version.
The only exception to this is any Bob Dylan version of one of his own songs when compared to cover versions. I liked Sheryl Crow‘s take on “Mississippi,” for example, but it’s nothing compared to his own version on “Love and Theft,” which is absolutely sublime. Anyway, no one can sing Dylan like Dylan.