B&W 805 models...

Pescolar, the Signature 805 is no longer current. They do not make any of the models listed except the 805S. Every model has it's own unique set of technology. Fife hit it dead on.

I just got a pair of the 805s.
They have a review from some mag on the B&W website about it, and mention the Signature 805 in comparison.
Generally to most current is the best sounding. They actually did improve it over the years.
(I like to sound, but do admit that I got a subwoofer to touch up the bottom end a bit. For Rock, Classic Organ, even the bass line in a Jazz group.. the bass is wanting a little bit. And I am not a low frequency maniac either! Just you gotta sit close to the 805s, or get some tone controls. My low frequency tone control is a subwoofer.)

Is the 805S better than or equal to the 805 signature?

"Is the 805S better than or equal to the 805 signature?"

Depends on who you ask. I've owned both. Both did things that I liked. My preference, I liked the sig 805 better. The 805S is still a fantastic speaker. Alot of people disagree with me. I think partly because most want to like the new stuff out there.

I forgot to add the B&W Silver Signature!

The Natuilus 805 is not necessairyl better than the Silver Signature. Depends who you ask.

Therefor the order from Oldest to Newest:

Matrix 1
Matrix 805
B&W Silver Signature SS25
Nautilus 805
Signature 805
805S