I guess I can answer my own question now.
I recently purchased a Parasound Halo P-3 preamp to try with my JC-1 monoblocks and to compare with my P/LD-2000 preamp.
The Parasound P/LD-2000 blew away the Halo P-3!
The Halo P-3 sounds thin and lacking in bass and dynamics compared to the P/LD-2000.The P/LD-2000 is warmer and has more body to the sound.The imaging is also wider and deeper.
The only areas where the Halo P-3 may sound slightly better is in the presence region of the midrange, and the top-end.
The P-3 has a more forward presentation to vocals, alittle cleaner vocal resolution, and sounds slightly more extended on top than the 2000. Otherwise the P/LD-2000 is superior in every other respect. Maybe it has something to do with the P/LD-2000's dual-mono, all discrete circuit design and massive 92,000 Uf power supply filter bank, compared to the P-3's large use of ICs and much smaller power supply?
The P-3 looks much better than the P/LD-2000! The P-3 is a sleek, sexy design. Very nice! But ultimately sound quality is what counts to me, and the 2000 is superior!