I had the LS-27, loved it. But as I upgraded other components, I noticed that the soundstage did not have the depth. I upgraded to the REF 6 which produced the results I wanted. I am running Wilson MAXX speakers and Rowland SS amps. I just replaced all my tubes in the REF 6, it was a little over 4000 hours. The power tube they recommend replacing every 2000 hours. I did try the BHK amp, but it did not have the ability to push the Wilson Sasha’s that I had at the time - I lost A LOT of punch - that is when I found the Rowlands. I did compare the LS-27 to the Rogue RP-5 before I purchased it, I thought the ARC was SLIGHTLY better (I purchased the LS-27 used). I have really liked dealing with ARC - they answer the phone and help with your questions (as does PS Audio and Rowland).
One drawback to my system is that poorly recorded music is going to sound poorly recorded, that was not as much of a factor when I had the LS-27. Some of the newer music is really compressed, that is not very nice to listen to (Pink's album before the latest one was unlistenable). But Dylan's latest bootleg series from Time Out of Mind is simply spectacular.
The ARC line stages have fewer tubes, so re-tubing will be a lot less expensive. (It cost about $600 for me to re-tube my REF 6).
I have to believe that you will be happy with any of the ARC Preamps.