Yes, I think it's worth baring in mind that a "greatest hits" and "best of" are two completely different things. Although, 'Greatest Hits' was only really a partial greatest hits, and 'Suedehead: The Best of Morrissey' was more of a singles collection than anything else...
I'm happy about this release (though I'm inclined to believe that it's not really coming out) because I hope he'll get it right this time. I think he came very close with 'The Best of Morrissey', but that was a US only release, and there have been plenty of great new songs since then that a new "best of" is worthwhile.
Over all, I think that both "greatest hits" and "best of" compilations serve their purposes, but I strongly believe that Morrissey's music is far better represented with the latter of the two. His radio-friendly "hits" contain some of his worst, least representative, songs IMO.