This is past history so take that into account. I was friends with Gordon Holt from the mid 70s until his death. Gordon was concerned with accuracy, the knid that sounded like the real thing on good recordings. Gordon did a lot of recording including many recordings of the Boulder symphony orchestra. He knew sound and he knew the original sound of his recordings. The last speakers Gordon bought with his own money were ATC 50A active speakers. He considered them among a handful, at most, of speakers that gave back what was on a recording. And this is not second hand. I was involved a bit in discussions with him when he was deciding to buy the ATCs.
I'll add I recall speaking to him about a review he did on an 5 speaker plus sub ATC system that he gave a rave review a few years earlier. I asked him if it was really that good. He told me yes. I asked him what he was going to do when ATC asked for the system back. He jokingly said he would kill himself. I was at Vegas CES the next year and in the ATC room speaking to the founder of ATC and told him that story. And he told me the system I was listening to was the one taken back from Gordon.
I have no doubt the Pass/Spendor system will be wonderful and you won't be sorry if you end up with it but the ATC system will be more accurate and what really matters to me personally will be more dynamic. I don't just mean it will play louder cleanly, which it will, but it's changes in level from mini to midi to maxi will be more accurate and will make good recordings sound more like live acoustic sound than the Spendor/Pass system.