This post is in no way a critcism of Meridian's sound qualities. All I'm saying is that there are now other products (Krell and Classe' for example) that have products in the $4000-5000 price range offering more features than the 561 and 568 with far more upgradeabilty and have been reviewed to have excellent sound. Do they actually sound better? I don't know as I haven't heard them myself.
Those guys at Classe and Krell still package their processor the way they make their 2 channel DACs, which is basically high quality D/A converts and good analog section.
Meridian's value is completely in their surround software. Those light-weights don't have the psychoacoutstic research background or digital data manipulation expertise to tackle any of these stuff, so they stick with the "preserving the signal" concept of 2 ch PCM world.
Those processors might tout upgradability, but will the ever provide new features in their software besides fixing bugs? We'll never know. So far, Classe and Krell hasn't provided much upgradability to their prior processors. They are not likely going to throw in new surround algorithms because they were not the ones that wrote them.
It's like looking at a F1 car and not seeing multi-memory power/massaging seat or leather lined foot-well and complaining about it.