I'm going to confess my ignorance. I didn't even know "When you say nothing at all" was a cover until now. I rather liked his version, but that's made easier when you have nothing to compare it against.
I don't really mind covers, because if like me you are musically ignorant, or just young (real reason, honest) then there would be lots of great songs you would miss out on if covers were banned. I agree about Tracy Chapman being better, but I always preferred Boyzone (or almost anyone else) to the Bee Gees' versions of songs.
This might seem hypocritical, but one of the few exceptions is Night Fever. They're version of it is the best, and no-one, even Will can't compete. Actually I didn't like Will's version, but that's not the point. On the whole the Bee Gees were (are?) great song writers, but aren't up to scratch on the performance side. Night Fever and Staying Alive are unusual in that they suit the cat wailing effect.
BZ classic Words - they did a good job. BGs version shouldn't be allowed on the radio.