"alt-preset standard -Y" VS "preset medium" Options

[ursus]

I'm using LAME (3.90.2) and "--alt-preset standard -Y" currently,
after much experimentation with the -V setting, lowpass, trying
--r3mix, etc. Overall I'm impressed with the high quality retained
with "-Y" compared to plain APS, despite the average bitrate
dropping from 220+ to a more reasonable ~180 ... I understand
some people (younger folks? :) with exceptional hearing might
object to some of the HF detail lost with "-Y" but I certainly can
barely (if at all) distinguish between APS / APS-Y.

I did try using the "fast" VBR mode (vbr-mtrh) via "--alt-preset
fast standard -Y" but due to some quirk of the vbr-mtrh mode,
the bitrate distribution (as viewed in EncSpot) shows a wierd
inverted slope from 192 and up (e.g. 320 > 255 > 224 bars).
Unfortunate, as vbr-mtrh is so much faster than vbr-old ...

I decided to try out the new "preset medium" with LAME 3.93.1,
but after just two encodes I've decided this sounds really bad,
muddy, background instruments sound like they are redubbed;
perhaps the average bitrate is just too low (usually <160)???
I thought, with similar optimizations as --alt-preset standard,
the new --preset medium should sound BETTER than APS-Y, but
so far this is not so.

Is "--alt-preset standard -Y" currently the best compromise?
Also, why is the bitrate distribution so sharply peaked with
the "-Y" setting, compared to "--r3mix" or "-V3 -b96 -h -mj"?
Maybe I am just ignorant in saying this, but shouldn't bitrate
distribution be falloff more smoothly on either side of the avg
bitrate peak?

I've thought of trying MPC or Ogg but the compatibility issues
keep getting in the way (maybe when iRiver provides Ogg
playback for the SlimX I'll reconsider).