Routeman21,
When buying my E-550 integrated, I have compared quite a few Accuphase integrated, i.e. E-350, E-450, E-550 and E-408 (the predecessor of E-450), and my preference was E-550 > E-408 >= E-450 = E-350 (by ">" I meaning marginally better). Because of the large price difference between the E-550 and E-408 (8500 vs. 4000 euros) I wanted to buy the older E-408 model. In the end I bough the E-550 as the dealer offered me a very good price for it (the E-550 was about to be replaced by the E-560).
I have also listen the E-460 and E-560 models (the E-560 I have compared directly with a E-550) and IMO my initial assessment is still valid, i.e. the sound difference between previous and current generation models does not justify the huge price difference. Consequently, my advice is to look for dealers that still have models from the previous generation, e.g. E-350, E-450 and E-550. You should be able to get these for 30-40% less money (probably a bit more on the 2nd hand market).
Hgeifman,
Only the top of the line Accuphase integrated, i.e. E-530, E-550 and E-560, which all run in class A mode, double up their current output as the resistance halfs, i.e. 30 watts into 8 ohm, 60 into 4, and 120 into 2. All these three integrated are more powerful than the specs suggest e.g. my E-550 made speakers like Wilson Sophia and B&W 802D cry like babies). However, if one listens to large orchestras or big bands at loud levels than the models from the E-4XX series are more suited, viz. they are much more powerful even though they do not double up their current output as the resistance halfs.
Regarding fully balanced designs, the preamplifier and power amplfier stages of all Accuphase models I have mentioned so far have a balance design (what Accuphase called MCS or MCS+ circuits). However, it seems that only models built like "instrumentation amplifiers" (again Accuphase jargon) can be called fully balanced designs. However, this is can be deceiving. For example, the E-550 model which is not an instrumentation amplifier design is superior to models like E-250, E-350 and E-450 which are designed as instrumentation amplifiers.
Best wishes,
Paul