MS PRO isnt the same as HP1000 (HP2). They are neutral, yes, but still kind of fun sounding anyway. Especially when you use flats or reverse bowls on MSPRO, they become much punchier and Grado like.
You can not beat HP1000 neutrality by any headphones, imo. They sound much fuller than MSPRO. The bass is just way stronger, MSPRO bass isnt exist, comparing to them. But MSPRO have more clarity in sound, which I call fun, but the highs are totally rolled off. HP1000 are much more upfront sounding than MSPRO, however if you use flats on MSPRO than you have something similar, not the same, but step closer.
What they do share is ease of listening, nothing happened to your hearing with them after many hours. One thing to mention. I tried to push MSPRO with higher volume level, using bowls, and they stay in great balance, where HP1000 isnt really love to be pushed, cos they loose their balance. Have an idea, because of their very upfront sound, so it is like having them build in in you ears feeling. Listening to HP1000 with low or mid level is the best, imo.
It would be very interesting to try MSPRO again, since I own Zana, so if anyone can send me a pair...just joking
I do believe that MSPRO will benefit really from better amplification, but they will never become HP1000, imo.
The bottom line is, if you like neutrality, but want some fun as well, MSPRO is your thing, while HP1000 is totally different level of choice.