I'm afraid I might have given some people the wrong impression, or discouraged some potential 737 buyers, and it's making me feel bad, so I want to clarify a couple things, and try to explain my opinion more clearly.
First of all, the black levels on the 737 do not suck, and none of the 737/837 comparison is intended to be a knock against it. I think dollar-for-dollar the 737 is the best bargain in TVs anywhere. Whenever I look at this 65737 and think about getting 65 inches of great quality display for only $1300, it gives me a warm fuzzy feeling inside. I have a $3,000 TV in the next room that despite it's excellent performance, does not give me that same feeling. Maybe it's because I'm a cheapskate at heart, but it's true. And getting a great *deal* makes getting a new TV even better!
When I first got the 737, I was impressed overall. Still am. Amazing value.
However, from a pure performance standpoint... the ONE area which left me wanting more... was the black levels.
But you have to keep in mind -- I'm the current owner of 2 Panasonic Plasmas, a Samsung A950 LED local-dimming, and recently took the Sony XBR8 local-dimming for a test drive... so I'm coming fresh off some of the best black levels in the industry. The Mitsubishi DLPs had some tough acts to follow.
In that regard, the 837 has filled the gap by providing deeper black levels. From the content itself, to the black bars in letterbox, to the black-out and fade screens of movie endings and credits. I'm not a pro, and I have no measuring equipment, but I would say it's on par with my '08 Panny plasma. Which is great! And it's not just dark, but the level of detail is excellent. In both movies and video games I can see a real difference in the dark scenes, or dark sections of the map on the 837. And I have not seen ANY negative side effects of the iris. Not once have I ever felt like anything looked or behaved unnatural.
However, for the majority of viewing it doesn't seem to make a difference. That's important to note, and good news for 737 owners because they won't feel like their always missing something. Most of the time, the two models look the same.
But when it does make a difference, it's really nice! Good news for 837 owners, because the extra money spent has a payoff they can see with their own eyes.
Given a choice, price no object, I think everyone would choose the iris. Why not. I can't find anything negative to say about it. Except the extra cost. The 737 is such a fantastic bargain, such amazing bang-for-buck... I'm not sure the extra performance of the 837 can match the extra cost between the 2 models, but that's a whole different story.
These are both great TVs, and there's plenty to feel good about for owners of each.