Benchmark / Anthem / Rogue

My story is very similar to stereo5. I have not heard the other two choices, but the Rogue RP5 was my main preamplifier for a couple of years. I have gone from all Rogue to all Mcintosh in that system. I am not sure that it is any better, but it is different. Originally I had the RP 5 feeding the Atlas Magnum KT 120 tube amplifier. I transitioned to the RP 7/Stereo 100 combination. Then to my current McIntosh C 2300/275 Mk VI System. Sonically, the RP 5/atlas magnum gave me everything that I needed. I liked it better than the RP 7/Stereo 100 combination. I found it to be more dynamic and full sounding than the more expensive Rogue pairing. I also used the RP 5 with several other amplifiers during the time that I had it and thought it was a very good preamplifier!

+1 on the RP-1 and Mullards from Andy.  It's what I run and been very happy with the setup.  I originally had the PS Audio Stellar 300 as the amp (tube class D combo).  Got a good deal on a Quad Artera A/B and swapped to that just to try.  Quad/RP-1 might be a little warmer for the most critical listener but the S-300 was a good combo as well, especially at low to moderate listening levels.

The RP-1 has very low comparitive gain- (7db)
The RP-5 has 10db.  
My personal choice was the Rogue RH-5 headphone amp line stage.
Phono stage optional but XLR in and out and the gain is selectable,
3, 12 or 16 which makes it match with more power amps.