One of the main things I look for in my entertainment systems is that they run quietly, and its promising to see a company develop a system capable of 1080p in a low sound output system. It is however disappointing to see that the system is just a reorganized PC, including multiple fans for cooling, which add the majority of decibels. As it takes on load (say, for running video in 1080p) and the fans kick it up to cope with the added heat, its going to increase in volume substantially, and as the system ages, it will start to make a fair bit of noise... not sounds I really want to be hearing as I'm engrossed in some sort of cinematic masterpiece.
Ideally, I'd like a system much like the PS3 to use for a entertainment hub, something the PS3 is actually quite good at doing and doing quietly as well. Its just too bad that its a Sony product.