The Pass X250.8 has broken in nicely.
The Parasound A21 was a good performer with my ML Classic 9's but the X250.8 is outstanding. I was also considering the Rogue M180 in my quest for improvements but due to the Classic 9's lack of internal bass amps I went for the Pass and I'm very happy with the results.
Compared to the Parasound, the Pass has much more depth, more clarity and ease, and is generally more musical overall. I'm hearing beautiful detail in my well know music collection that I did not know was there and now is obvious. The tone and harmonics on piano, violin and other difficult to reproduce instruments seem perfect to me. The bass is richer and more tuneful where the Parasound was perhaps quicker but more mechanical.