I also have a 5200 (factory refurb) which has given me nothing but pure enjoyment for the past 3 years. I'd agree that in the past, Marantz seemed to be a little behind in adding bells and whistles, when compared to other manufacturers, but looking at their current offerings, they seem to have caught up. And they've always been known for performing exceptionally in both home theater and stereo applications.
As for power, Sound and Vision mag tested the 5400 (last years version of the 5500) which was rated at 90watts x 6 channels. Its output, measured with 5 channels driven until clipping (tested at 1 KHz into 8 Ohms / Clipping point = 0.3% THD + Noise (APR '01 - pg.44)) was 103 watts per channel, so it actually outputted higher than claimed. So you should rest easy there. Also keep in mind, I don't think Marantz design their receivers to push 4 Ohms, to if you have 4 Ohm speakers, you might want to look elsewhere.
