Rarely does a further new version, changed to make it "theirs", so it simply isn't the same any more, come close to sounding as good to me as the one I first encountered and enjoyed. I think it is because a particular song/rendition is acknowledged as good that others consider it worth have a bash at, but it is the fact that it is good that means they simply fail to come to the same standard. They should look for a presently poor effort of something with potential to make their own.
I never liked Leonard Cohen singing his song Hallelujah and then Jeff Buckley recorded it and I found it marginally better. It wasn't until K D Lang recorded it that I realised what a great song it is. Even so, her best version is on the album "Hymns of the 49th parallel", I've heard her sing it live and IMO the recording is better.
//Rarely does a further new version, changed to make it "theirs".....//
it does happen though - Roxy Music had a good go with "jealous guy", and Dave McCabe of the Zutons was often asked before concerts if they'd be doing their "amy winehouse cover".