i agree with Albert and some others that very good or great vinyl is quite a ways beyond the best digital avalible today......and that would be SACD.....not Redbook....and these formats are not really that close.
i have not heard better Redbook than my Linn CD-12, it has a natural clarity and overall ease and drive that does mimic sacd......but.....the resolution of MOST sacds on my Marantz SA-1 is quite a bit better. even analog tape based sacds are generally better than the best redbook can do.
the recent sacds released by Analog Productions are a good example; "Waltz For Debbie" and "Chet" are 2 of the most familiar cds to myself and probably most of you. i own 3 different cd versions of "Waltz" including the XRCD and 2 cd versions of "Chet" including the gold Analog Productions versions. these 2 new sacds blow away the cd versions in almost every way; lower noise background, more detail, deeper soundstage, more believable instrument presentation, etc., etc., etc.,......
the negative about sacd is the slowness of new releases, not the performance. i will say that recent improvements in the performance of my system has made the differences between the various formats much more pronounced; a year ago i percieved that the CD-12 was closer to the Marantz SA-1 than i now percieve it to be.
in my system we sometimes start with the cd of a performance, then sacd, then 33rpm vinyl, then 45rpm vinyl.......it is quite an eye-opener to hear the performance come alive.....the differences are not subtle.....they are significant to me and other listeners.