ARC Ref 6 VS. Vac Renaissance MK V

Have heard the Ref 6. Was super detailed and transparent but very forward. Have not heard the VAC preamp. Thoughts? 
Mulveling, in terms of sound on the Ref 6: how did it compare with the VAC equipment you’ve listened to? Particularly the line stage? Thanks for your input. 
Like I said, I think the Ref 6 is notably better than the Renaissance III. Though I didn't own them at the same time, I had a Rogue Hera II for reference against each. The Ref 6 is the most detailed and has the best clarity; exceptionally clean and clear sound. Fast and free of all grain. With the new VAC phono, it also displays better extension on both ends. Dead neutral tone. 

The Ren III a beautiful midrange (as all VAC does), good treble sparkle (maybe a bit editorialized) but perhaps a bit of bloom in the bass. Its built in phono stage, like the new stand-alone stage, is decidedly on the warm side, but man I love their phonos. A more romantic sound overall. 

The Hera II was more neutral than the Ren III, with better bass, but has a slight haze to it (like SS haze), maybe from the fact that it's too high gain for my 96dB speakers and noise/microphonics was ever present in that setting. This preamp matched best with the Rogue Ares phono, not surprisingly.
Has anyone compared the current stuff like VAC master preamp directly w arc ref6, ref10?
I’ll probably be borrowing a VAC Master from my dealer soon, to compare to my Ref 6. But I saw a photo of the inside and it looked a lot like the Ren V circuit, with the main difference being PSU (much in favor of the Master). The Ren V SE might be an interesting option, since based on the SE vs. non SE on the Renaissance phono stage it raises the parts quality a lot (I think even better than Master in some cases) and makes it sound more neutral and detailed.