Some musicians get all tied up in knots about the issue of equal temperament. I think they miss the point.
Equal temperament on the modern piano is like any other temperament on any keyboard instrument: it is as satisfying as the player understands it to be.
I have heard too many people playing on "better" temperaments who couldn't care less: One player of the fortepiano confided to me that she couldn't, to be honest, tell the difference.
I can tell the difference, as I tuned and played a beautifully in-tune harpsichord for many years and loved every minute of it. Then, when I took up serious solo piano playing my ability to tune that other way totally disappeared, so I stopped doing it.
I love the sound of the modern piano, always have.
I keep my ear "clean," so to speak, by indulging in a cappella singing tuned as pure as the ear allows.
Equal temperament became an issue when people stopped listening to the true riches of the modern piano and began to impose some standard-notation-visually-delimited definition of pitch on anyone who would sit still long enough to go along with it, whether orchestral instrumentalists and instrument makers, or choruses.
One can combine sounds of varying temperaments: I have done it playing chamber music and accompanying singers. Whether it works or not is up to the ear (i.e., the touch) of the pianist to determine.
