in the past, no doubt 15ips 1/4" tape master dubs have been supreme in my system. high quality tape transfers simply provide an uncluttered view into the music in every way; particularly with the continousness and completeness of musical parts. also the dynamic energy and tonal truth from tape is on another level as it simply has this amazing density of information. your brain does not need to do much work when you listen as there is less of reality missing......the relaxation you mention.
This is where the digital medium still has not come of age. And that is in the sense of a typical collection of playback gear being able to do this effortlessly. At the moment it is still a major, and difficult exercise to drag digital reproduction to this performance level, not because there are any problems with the source material, but because the industry is painfully, irksomely slowly, moving forward in coming to terms with some real issues hampering the ability for digital to sound top of the class every time.
Part of this is that is the human prediliction for being sloppy: close enough is good enough. This can work brilliantly with analogue, but is disasterous with digital. Again, digital sound takes no prisoners; if you don't do it properly -- and that doesn't mean hooking up the most expensive DAC you can find -- then CD, etc will never do it for you.
One of the very, very clear indicators of this problem the industry has, are the stories by people who enjoy first class digital sound being those who either themselves, or via efforts by others, had major tweaking done of the digital components: the industry itself is still not interested in sorting these issues out, the people designing the gear are still not listening hard enough ...
Frank