In my personal experience I can definately tell the difference between 128, 128vbr, 160vbr, and 192vbr... 128 sounds really bad to me, while 160 is tollerable and 192 is almost-perfect..

Just my two cents worth.. All my newer cd's are encoded in 160vbr (audiocatalyst) or 192vbr depending on how much I like the cd..
-mark

...proud to have one of the first Mark I units