I really love the PS audio stuff, I'm very pleased with the DAC and the transport; I also want one of their power center but since in Switzerland we use country specific power outlets, I would either need to buy an EU model and change all my power cable or contact them to see if they can build custom.
What the memory player does is it pulls data from the disc basically reading the files not as audio files but as raw data like a computer would and then write to a memory buffer which is then used to feed the DAC using I2S, from what I understand the advantage of doing that is first it's eliminating the error correction happening when reading from a disc and also helps reduce the jitter, at least that's how I understand it, there's actually a pretty technical review on 6moons if you're interested in more details, to my ears the combo just sound beautiful
The memory player is not a server but their DAC has a bridge option which basically is a fancy ethernet card that you insert in an expansion bay that let you stream any audio file that you have on your home network, I have mine connected to my 24TB NAS were all my music and movies are stored and it works very well, they have an iphone/ipad app that is surpisingly well done, I controll it with my Ipad and it's pretty nice, also since they both have internet connectivity, they can display cover art and album info on the front touchscreen.