I own the Synchrony Two's and have listened extensively to the 805s on various different amps. I was considering buying the 805s before the Two's were launched, however the overall cost is blown out by the need for a super powerful amp, and plus the bass will never go as deep as the Two's. For me the whole music enjoyment factor changes with deeper bass. The 805s are great for acoustic and vocal music, and even pop to some extent, but you get so many more sounds with deep bass.
As for the Synchrony Two's:
(1) I run them with the Simaudio I3RS and they are a terrific combination. The Two's are not an ultra-detailed airy sound that shows all the tape hiss on a recording, but they reward you with good amplification and decent cabling. Just about all my cds are very listenable on them. The combination is totally non-fatiguing as well.
(2) They are excellent for home theatre purposes as well, even in a 2-channel setup. On a good amp the separation and 2-D imaging is incredibly good, and the midrange is very open, so much so that you don't even require a center-channel speaker. With the bass going quite deep I don't need to run a subwoofer. Vocals on movies/tv sound incredibly realistic.
(3)
The PSB's have 3 port plugs in the back of each speaker so you can tune the bass to your room. They come with one pair of plugs, so I bought 2 extra pairs. Depending on how much I want to annoy my neighbours, I run them with either 2, 4 or 6 plugs, and you can really notice the impact. With the bottom ports open you get the deep bass impact, and with the middle ports open you get more out of the mid-bass. Anyway this gives the speakers tremendous flexibility.
(4)
The overall sound of the Two's is a bit on the laid back side (the One's are a bit more forward in the midrange), however they are still incredibly dynamic. The 805s is probably more forward sounding as well as compared to the Two's.
(5)
If you can stretch your budget, then get the Synchrony Ones, as they have a separate midrange driver so you will get a smoother and more open and detailed midrange. They also have even deeper bass, and are more dynamic than the Two's. However they are a bit bigger than the Two's and they probably can't be in a small room - but you can still tame the bass with the port plugs.
(6) If you get the Two's, get speaker cabling that is not too energetic on the top end, due to the use of the titanium tweeter and the slightly laid back sound of the midrange. That tweeter is incredibly accurate and grain free and clean, however it is still metallic.
