For those who are having issues streaming HD I can tell you that it for sure is not system-wide. I streamed my first HD show last night and it started up in about 10 seconds or less (same as Netflix). The picture quality was very impressive on my 55" LED TV, and sound was great through my 5.1 Home Theater system.
One advantage over Netflix streaming is that after pausing the audio remained in perfect sync to the picture, which isn't normally the case with Netflix (in my experience). The fast forward, rewind, and skip ahead and back functions worked flawlessly also with no buffering required. It never buffered at all, except for the few seconds before start up.
FYI, I use Time Warner 10/1 internet, through a Netgear wireless-N gigabit router to the Dish Network wireless dongle on my 722 VIP receiver (which is one floor above the router a few rooms over). From a performance standpoint based on this one experience, the streaming itself is just as good as Netflix, better if you take into account the audio remains synced as mentioned before.
I will join the ranks of those who hope the interface gets a complete overhaul in the near future as clunky is perhaps an understatement. The website/queue functionality is also not up to par with Netflix but is sufficient for now. The way I see it, we're getting a great deal (those who were already paying Platinum customers, in particular) and are being used as "beta-testers" for this new system. I'm totally cool with that.
Regarding the discs...during football season I probably won't watch three out at a time hardly ever, especially considering I have several movies on my DVR, and a local store less than 5 minutes away. But to show thanks and support to Dish/Blockbuster, I upgraded to 3 out at a time anyway. As they say, consumers vote with their wallets...and I for one am voting positively for this new offering.