Here is my situation:
I have recently setup unblock-us, Hulu Netflix, vudu etc...
I am on Telecom and getting a speedtest of around 8-12Mbits/sec from the states (LA)
I have been playing with the apps on:
Samsung Blu ray player
Galaxy note.

So far the PC gives the best consistent experience.
Vudu on the Blu-Ray works well - Netflix buffers( drops frames) Hulu just buffers...and plays again.

I am thinking of trying a Roku or WD TV.
Downside of the Roku seems to be no digital audio out (my amp doesnt support audio over HDMI) so I would be stuck with simple stereo. No BBC Iplayer, 
Upside: plenty of Apps and the new search feature looks really handy

WD TV Upside : Does have optical audio out and BBC iPlayer.
Downside: Less apps that I can see.

Is the WD TV you can by from PB tech/Ingram region locked in any way.?
What is the comparative streaming ability of the two units?
Am I naive to think that any 'streaming-box' will provide as good a performance as a reasonably powerful PC?
I am about to ditch an Xbox elite (about for years old) - would that make a better streaming device than say a Roku?