Definitely go for it Doug, I've had for a month, and although there are a few bugs being worked out, the HD playback looks amazing and makes it all worth it. The SA8300HD box also changes channels quicker than the SA4200HD and also displays the video resolution on the display of the box.
Also, a good place to check out is the
Cablevision_Digital Yahoo! Group, a tech guy from Cablevision, Wilt Hildenbrand is kind enough to answer questions and also helps out with people who have had customer service problems.