I purchased one of these at Sears a few months ago, on sale for a whopping $299! I'm more than satisfied with it for that price, but I've learned a few things about it that might help somebody else out.
At first, I had trouble getting audio to work over HDMI, but I've since found that this issue was caused by my older laptop and/or the video and HDMI drivers that go along with it. I've since disabled audio to the TV via HDMI at my receiver.
However, when I initially enabled audio out over HDMI at my receiver, the TV goes into a very pronounced overscan. I could easily eliminate the overscan in the service menu, though. For what it's worth, the service menu is accessed via Menu-0-0-0-0.
The overscan issue will intermittently arise again, regardless of any settings I've tried at the laptop or in the A/V receiver. It only happens when I first power up the TV and laptop, and only once in every three or four power cycles. So I have to revisit the service menu periodically to fix the issue. This would not be a wife/houseguest friendly solution! I've read about other Seiki TVs having an issue with HDMI overscan, and many of them were resolved via a firmware upgrade, but none seems to exist for this model.
I also had an auto shut-off problem via HDMI - it wouldn't auto-shut off - but this turned out to be a receiver settings issue, and not at the TV. Note that it does seem to take a good few minutes longer to power down when connected via HDMI than it would via a VGA (DB-15) connection. But it does work, so if you saw my earlier, pre-edited comments, you can disregard that issue.
I couldn't find a service manual, or even a user's manual online. (I have the printed UM.) Specs are still listed on Seiki's web site here:
If anyone ever comes up with a fix for the overscan issue, please chime in!