Hi Steve - First of all, I have a MAJOR problem that causes me to analyze the performance of my gear. Over the last year, I have switched amps 5 times and speakers 3 times (not to mention DACs, SACD players, speaker cables and interconnects. Since "ugradeitis" is normally in play, I always find a way to justify these frivolous expenditures - and I have a very understanding wife! Even now, I am tempted with replacing my Accuphase E-600 with the $21,000 Luxman MQ-300 tube amp.
During my quest, I have auditioned or owned Arcam, PrimaLuna, Luxman, Gato, Esoteric, Pass, Plinius and Accuphase integrated amps. I still own Gato AMP-150 and PrimaLuna DiaLogue Premium Integrated amps.
Without going into the reasons and circumstances for each purchase, I will tell you that my biggest regret was not leaving well enough alone and keeping my Luxman L-590AX and D-06U SACD player/DAC. Several amps and $$$$ later, I have incrementally gone up the sonic "food chain" but not by orders of magnitude. If I had to do it again, it would be the Luxman L-590AX II and I would call it a day.
Other than the value proposition the Luxman has over the Accuphase, here are my thoughts on the differences:
Overall realism and purity of sound: Probably a tie.
Bass Authority: Accuphase
Soundstage: Luxman
Warmth: Slight edge to Luxman (more "tube-like sound)
Detail: Slight edge to Accuphase
It is important to note that synergy of components, interconnects and even power cords will have an impact on performance as well as room acoustics. As others have mentioned, TAKE YOUR TIME and enjoy the process. Work with a couple of reputable local dealers and always try to audition the gear at your home.
The most important thing to remember is that NOTHING that anyone tells you on this forum is gospel. What appeals to your ears is the only thing that matters. Having said that, everything sounds great until you hear something better so make sure you can establish the point of diminishing returns (something I obviously cannot do!) The good news is that you are considering some really good gear and your budget will allow to assemble a first-class system!