I've had the Mits 65734 for a couple weeks now and absolutely love it.
The 833 will give you a whole lot of proprietary technology over the 733. It's up to you to decide if it's worth it. Have a look at the website (
733 link,
833 link) to read about it. Mostly it's things like Dark Detailer, Perfect Color, Perfect Tint. Things along those lines. The 833 also has a fourth HDMI 1.3 input and a Firewire connection. Another difference is the 120hz refresh rate of the 833 over the 60hz on the 733.
I went with the
734 over the 833 and I couldn't be happier. It was most of the additions that the 833 has (Dark Detailer, Perfect Color, etc), but doesn't have 120hz and a firewire connection. For me though, I have nothing that uses a firewire connection, and 120hz didn't justify the $800 price difference (Check amazon for prices, I had a great buying experience getting my TV from them: no problems at all).
All in all: I absolutetly love my 65" Mits DLP. It looks beautiful, was easy to setup and calibrate, and for the price (hell, regardless of price) I don't think it can be beat.