Not everyone hears the same PS1000's (or other Grados for that matter), because many don't drive them with a set up that matches them well. With the right amp and DAC, Grados do not have strident highs, they are smooth and clear, and they have a much larger soundstage than many report. They require an amp that has very low impedence and high current output (like the RA1, or X-Can V8, or various others), which prevents clipping, tames their highs and expands the soundstage. With a poorly matched set up, they sound harsh and rough, without any soundstage, which is the result of clipping and distortion, because such amps can't control their drivers well. Virtually every comment you see, which reports such aberations in their sound, is the result of a poorly matched set up. Which is the reason Grado offers matching amps to drive their phones - though, you can find amps that drive them better than the RA1.
I don't think that's accurate. most negative comments on the PS1000 have been from members who have heard lots of high end headphones (the PS1000 are pretty expensive for people new to the hobby to try out) and have been connected to very good amps and sources.
To say that "virtually every comment you see" that is negative is a result of a poorly matched setup is a little bit insulting to the people who have commented on them.
When I was considering buying the PS1000, and when I owned them, I read lots of comments about them. And they were impressions from members who have better amps than the RA-1, to be sure.
The negative comments were not that the PS1000 has no soundstage or was clipping or rough. The comments said the PS1000 have a big soundstage, but they also have large treble peaks and valleys and exagerated bass kick with rolled off sub bass. Not surprisingly, people in the market for a TOTL headphone may not like such obvious colorations. Some might, though.
Connecting a PS1000 to an RA-1 won't "fix" that sound. that's the nature of the PS1000. You can get an amp that shelves the treble beyond what it should and then the PS1000 might sound smoother but a neutral amp will reveal the PS1000's character. I'm not just basing this on other member's comments but on my experience, as well.