I've had my 552XVT since January but just found this thread today (but I'm viewing it on my TV since my laptop's connected to it!)
Anyways, in addition to only getting 2-channel PCM sound from Vudu and Amazon, I just activated Netflix a couple weeks ago and the sound on everything from that has been in MONO! I know Netflix can't do 5.1 but it can at least do stereo, but there's absolutely no channel separation on anything and all the sound comes through my center channel. Just for kicks I turned on the TV's speakers and it comes out in mono through those as well. I've checked about 25 movies which I've seen before and know how they should sound, and hooking up the computer they come out in stereo through that but the picture quality isn't as good as it is through the TV's app.
I've been complaining about this on both Vizio and Netflix's Facebook pages for about a week, but nobody seems to know what the problem is and none of the other people who've used Netflix have commented about the sound. I called Netflix's phone line the day I activated it, and they said I'd have to let Vizio know about the sound problem. Called Vizio this week and they said Netflix has to update the software to fix the problem, so not sure who to believe.
Is ANYBODY getting stereo audio out of Netflix? I'd think the people on this forum would notice more than the people who've been posting on Facebook. I'm not sure if this problem is isolated to just my TV or if it's affecting every one of this model, but if it is it seems that SOMEBODY else should have noticed it by now.
All the VOD services this thing has are pretty neat, but I'm not going to pay for any of them until they work like they're supposed to!