Retail is $6550. My understanding is that the 360 went through a number of revisions leading up to the "ESP". As in the past, Keith does not share or publish specifics on the upgrades. My impression, based on conversations with Keith over the years, is that he spends hours and hours experimenting with different critical components in the signal chain and that when the cumulative improvement in performance that emerges is sufficiently large that parts combination becomes the next revision. His "excitement" during my phone conversation was about a leap in performance that resulted in the "ESP" model reviewed above. One thing I should also make clear for those who are not aware already--Keith's product support is legendary and he offers upgrades in revision status to his clients at very reasonable prices. Thus, my 3A, which was originally an "R02" was upgraded by Keith to an "R03" with a very quick turnaround in his shop.
@manfred1020 You can see my system profile here http://systems.audiogon.com/systems/3224 which should help with your synergy question. I also used the VTSP-3A (R03) with a Modwright KWA-150SE which was a nice pairing. By design the VTSP-360 (ESP) and VTPH-2A work extremely well together and it surprises me that so many people use Keith's phono stage with linestages from other manufacturers. (Of course I did this for a while myself using various Modwright linestages until I picked up a Herron). Hope this helps!
I also have the 360 ESP and would confirm dodgealum's findings. I have about 150 hrs. on the preamp and it's an improvement over the 3A-03. I was thinking about going the integrated route, but I couldn't find one with all the features I wanted that are available with the 360 ESP. This was a direct replacement in the same room. My next step will be to replace my original Herron 150 amps upgraded to M1's with his new M2's.
I've been upgrading my analog system and was in need of something for my new SL-1200G turntable to go into. Researched for a long, long time. Keith's gear (and Keith himself) have gotten so much love everywhere I've been able to find any opinions about them, that I called him and ordered a VTPH-2A phonostage, and because my MSB Analog DAC would not be a good match for that as far as input impedance, I also ordered a VTSP-360 preamp and a couple of his IC's. Should get 'em in a few weeks; can't wait!!!! But I have to, and I know they will be well worth it.
@skucie The benefit of the switch will depend on how your outlets are wired. It may have not effect at all, as in my own situation. However, it is nice to have the option to align polarity if necessary.
@dodgealum thanks for the reply. So, assuming one's outlets are wired correctly, does the sound suffer if you flip the switch (assumedly putting all the other equipment on the other AC phase?)