mazer:
abr
is vbr, just a different "form" of it
abr sets forward the concept of "unlimited" bit reservoir.. this means that complex pieces of music that require more bits can now be coded more accurately
however, when lame 3.88 beta was released, a few people reported hearing "ringing" artifacts with popular abr settings like --abr 192, 256, etc ... from what i heard --nspsytune supposes to fix that but i haven't tried it out yet
my ideal abr command line in lame 3.89 would be
--abr 224 -b 160 -m j -q 0 --nspsytune --nssafejoint --lowpass 19.5
file size will be a little big but sound quality should be (in most cases) fairly solid
to avoid clipping, if the peaks of the original are over -0.3db (or 97%) try adding --scale .90 to .93 to the command line
besides, i'm still using cbr with both lame or producer pro, depending on me mood and whether i have patience to wait for producer pro
abr is good though if you want the best sound quality vs. less disk space wasted