Some people here are talking of slight perceptions in the change of frequencies. Of those people, how many have bought a PRS that has a an ebony fretboard, cocobolo fretboard, rosewood neck, maple neck, ash back, or a private stock with some really weird combination of non-traditional woods? Each and every one of those alters the voice of an instrument in a greater way than going from standard to stainless frets do. But, people aren't speaking up against PRS with roasted flame maple necks and the extra snappiness. Speaking of Paul, he talks of using frets he believes sounds the best and that needs to be some static thing, yet releases guitars out of the factory with all the previous iterations I mentioned and more. Paul doesn't use stainless because he knows he can sell guitars to his fanbase just fine without having them on the guitars. Music Man uses stainless on everything now, because their particular players not only demand it, they expect it. It's that simple. You gauge your base and proceed accordingly. The tide, however, is definitely changing.
Forget everything else mentioned in this thread. Stainless steel frets are a peace of mind thing when you buy a heirloom quality instrument. It's peace of mind that you don't have to bring it to a tech in 10 to 20 years for a fret job and the possibility that person may damage the neck.