Here's what I can tell you, FWIW; I spotted a very positive review of that Pass unit earlier in the summer so I called an audio engineer friend who has no connection with Bryston for his thoughts. He was of the opinion that Bryston's preamps are probably better based on the respective engineering philosophies as he sees them.
I was happy with my BP25 and only sold it to buy an SP1 when it was just coming out. I'll skip the long story and just say I now have a BHA-1 for a preamp. It sounds amazing and has all the features I presently require. Hope this helps.