My 805 Sigs were powered by the McIntosh 352 amp and also I use the McIntosh C2200 (tube) preamp. These were were in my home. During that time I added a sub woofer to my system which really impressed me even more.
I've driven my N805Sig's with an Aragon 800BB, NHT A1 monos and a Sherbourn 7/2100 (present). All listening was done in my dedicated room (16x20) which has wall treatment (thanks Rives). Pre was an Anthem AVM20. Source was a Modded Philips 963SA and cables are Cardas Golden Cross. Power cords by Virtual Dynamics. They sit on custom Amboyna Burl stands.
A lot of people fault the N805's and Sig's for being bright. I find them very acurate and revealing. They will highlight any deficients in your system or source material. But, when you get it right they are soooo good. Soundstaging is huge. You really have to take the time and effort to set them up correctly. Most people don't want to do this; they just plop them down on either side of their rack and then bitch about how bad they sound. Also, they need room to breath. They should be out in the room at least 3 feet. They take a long time to burn in; about 300 hours. Good stands are a must.
I've used my S805's first with an Arcam FMJ A32 and now with a McIntosh MA6900 integrated. Source is a Proceed CDD transport with a MF A324 DAC. Cables are Red Dawn ICs and Audioquest Granite double biwire and Illuminarions D-60 digital. They definitely demand quality amplification, being very revealing but I enjoyed them with the Arcam and now the whole system went a step further with the Mac. I find them very detailed and natural sounding. B&W's are forward sounding and for some a bit bright so choose cables and other equipment with care (listen first if you can) as with any other piece. I don't find them overbright in my system.
We found some of the same results as above, placing them out in front of the stereo rack was better than more of a flush position with the rack, which in comparison caused them to sound closed in.
There have been a couple mentions of the posibility of brightness, this was never an issue during our listening and never once came to either of our minds.
As Gustavog stated, I found them to be tilted towards forward sounding.
Again, I was quite impressed with them.