It's a fair criticism
You don't say how you viewed your iPlayer material. In other words, who was converting the iPlayer stream into a format your TV could accept? I ask because the iplayer stream is .flv (adobe flash) so the quality you see is going to be dependent on how the stream is decoded. This, I think, screws up your bitrate assumptions from the not-blog. It also makes quality comparisons extremely difficult.
Yes, I had no idea how to allow for the effects of data compression and concomitant decoding at any point (or points) in the processing of the incoming video bitstream. I therefore did what any half-decent programmer would do in that situation: falling back on data encapsulation I ignored the whole aspect, treating the system as a black box (which it mostly is!).
But I also currently retain my skepticism1 about the wisdom of the apparently inexorable trend towards the "convergence" of TV and networked PC in the living room. I cannot deny, however, that fantastic progress has been made in the last five years or so. Starting with the early, clunky, Home Theatre PCs and culminating in ridiculously-tiny USB dongles that incorporate much of the same function. I note, however, that the usability of the various Media Player GUIs I've now had the chance to play with still leaves much to be desired.
As my chum quite rightly goes on to remind me:
On my system I end up comparing how well the Onkyo can upscale different bitstreams, which is a dubious test at best and pretty futile because except in the most extreme situations I can't tell the difference at normal viewing distances (I am not interested in comb distortions you can only see with a magnifying glass when your nose is pressed against the screen). About the best I can do is compare the statically converted material from get_iplayer (720p) with a direct streaming version of the same program. Even this is difficult because although I can make VLC play the stuff at natural resolution (ie 1280x720 pixels) I've not found a way to do the same thing with the iPlayer and comparing the full screen versions is again a case of comparing the VLC and iPlayer upscalers.
This is all an interesting exercise in nerdism, but in the end it doesn't matter much (at least to me) providing whatever shows on the screen is acceptable. To that end I find both statically decoded material shown via WD and Onkyo and dynamically decoded stuff processed entirely within the Toshiba are both eminently satisfactory. Maybe next time you are over I will set up an A-B comparison of the live iPlayer via TV and WD to see if we can see any difference.