B&W Nautilus 804 - how good are they

I am currently listening with:

Infinity RS625

Tektron M Lore

Athena Technologies Audition Series AS-F2-1

Mission 774

Subwoofer Dayton 18-22 sealed with L/T1300 amp

I am considering buying (very low end of the price range, but substantial investment for MY budget, 1 hour away, prior audition) a B&W Nautilus 804. 

i want to bring one pair of my speakers, but have NOT gone through enough side by side testing to determine which of the above my FAVORITE is. Main system is in VERY large (volume) room (2.5 story great room, open to hallway, 2.5 story entry, kitchen). Onkyo TX-RX810 amp. 

Before spending time and effort to audition:

a) which of the above should I bring and why (just opinions obviously)

b) can I expect the Nautilius 804 to be a major upgrade to any of the ones i have? 

Likes: soft highs (no sharp "ESSESS"), 'painting a large picture'.