I am replacing my current amp with a Yamaha. The options are both secondhand amps. One is the DSP-Z9, which was bought in 2005 and is in pristine condition for £600 and the other is the current Adventage RX-A2020 bought 5 months ago but slightly more expensive at £650. The Z9 is from a mutual acquaintance and I has heard it before and I know I was blown away by it. In fact, until I read up about it, I wasn't even aware that it had no HDMI and it was all done via optical from the source! I haven't heard an Adventage a2020 yet, but I have read enough to know that I can sell it off without incurring a loss at the price I will be getting it, atleast until the next model comes around. Plus, it has got HDMI, networking and is black which my wife can't moan about. What will you go for? A monster classic, with low specs and higher mileage on it or a younger power with fresher perspective at my price range. P.S. I will be using them to power the Monitor Audio Gold surround which I will assemble slowly.