Yep. I'm happy. Marantz does fine for me. If there isn't much to be gained, I wont mess with it.
I've posed that same question amongst the varoius forums myself. I have two systems. I did some tests without any preamps, different preamps, swapping different DAC's amongst the systems, etc, etc. (Both my preamps have been serviced, tested, caps replaced as needed, so on and so forth.)System synergy is often underrated. A preamp does have a sonic footprint, and I favor the sound of Marantz. Here's what I found:
My basic system, which consists of Marantz 250M solid state power amps and JLB L100 12" 3-way speakers sounds best "to me" when used with my Marantz 3800 solid state preamp.
My uber system, which is a triamp system with Mitsubishi DA-A15DC solid state power amp on the LF horn bass bins, a Rotel RB-991 solid state power amp on the dipole tweets, and a Dynaco ST-35 tube power amp on the mid horn sounds best "to me" with my Marantz 3300 solid state preamp.
There are simply way two many permutations possible to be able to test everthing and still have a life. Add to that, the fact that doing audio A/B tests is a flawed concept to begin with. If it sounds good now, I'd stick with it.