More food for thought.....
You talk about a "server" in generic terms, and you are dealing with a computer with expandable storage space. How much space does their server contain? Today's Blu-rays come on 50GB disc, and with 4 times the data, that's 200GB per movie... 5 movies comes to 1 TB. Is it expandable? Hopefully, it would be, to allow expansion of the future titles available, allowing the consumer to build their 4K "library" as we do with our music & movie libraries now. What interface will be utilized for storage expansion? USB 2.0, USB 3.0, eSATA or firewire? What kind of limit, if any, on the number of/size of external HDDs attached for this future library expansion? It will have a network ready interface to be able to "download" the future content promised to be coming this Fall (both converted as i believe most of their 10 offerings are, and native shot 4K movies).
... and I'm not even going to approach the cost of the content, the cost for the connection (speed & data limits), or the time needed to download the massive amount of data a 4K movie would contain.
But don't get me wrong, I'm all for this, and appreciate all "early adopters". Hopefully, my Hx 909 will last half as long as my previous set (a 27" Trinitron CRT that still has a very good picture after 22 years). Time will bring the prices down, and I expect them to be affordable to the average consumer... remember 8K is just around the corner!