I've been enjoying the liquid mid-range/3D imaging/transparency/realism of a tubed top-end(Cary SLM100's, modded) and the speed/definition/extension/power of a MOS-FET bottom-end for the past 19yrs(was a Hafler DH-500, now a TransNova 9505, both modded). The last combination included a Placette Passive Linestage and a Dahlquist DQ-LP1(modded, that had been in my system since 1981, for lack of anything in the marketplace to better it). My latest system iteration has replaced those last two pieces with a TacT RCS 2.2Xaaa. I eschewed signal manipulation and all things digital(in the home audio environment) for many years. The TacT(soon to be modded) represents a major paradigm shift, but one that has yielded major sonic(and flexibilty) benefits. Hopefully- The NOS Holy Grail tubes everything is stuffed with will provide the 10kHrs they are rated for, so I won't have to mortgage the house to replace them(TungSol 6SN7GT round plates, Sylvania 6SN7W tall bottles, six Siemens CCa's). The only thing I can see having to replace might be in the Source Dept, if/when technology takes a quantum leap there.