All I can say is even with a 7Mbps connection, streaming is unreliable with my Sony Bravia XBR9 TVs. It works sometimes all the way through a 2 hour movie, when other times it stalls on a 1 hour TV show midway through, and repeatedly thereafter.
DSL normally is less than 7Mbps, so anyone with DSL trying to connect to Netflix, I would attribute it more to the connection speed than anything else, as well as the Netflix programming for the streaming.
I would contact Netflix and let them know not everyone has Cable or Fiberoptic to be able to handle high speeds, and many stuck with 384 kbps DSL still. I would certainly hope that with any streaming device they can handle the minimum broadband speed. Cause if they can't what hope do we have for 3G devices such as iPad 3G? I don't expect dialup to work, but at least minimal DSL shouldn't have that much trouble. Way back when, when I had a 384 kbps DSL, I was able to stream the Quicktime trailers in Mac OS 9 of some movies. No reason Netflix can't talk Microsoft into improving Silverlight to handle streaming better. We as customers who have slow broadband internet just need to let them know when they aren't serving everyone with broadband.