My friend Jared made a great comparison video about the Marshall 5″ V-LCD50 HDMI and the new SmallHD DP6 monitor. Both monitors are made for the new HDSLR’s. I want to buy one soon, but don’t know which one. Perhaps the video helps you for your decision. I like the Marshall panels and their ergonomics (knobs on the front…). I also had issues with the SmallHD DP1 in the past (bad panel, buttons on the back…). The first reviews of the new SmallHD DP6 are great, perhaps I should test both of them before I buy one. The marshall one costs $ 600. Good price for a good product! The DP6 costs $ 899 with HDMI, but you also can buy it with HDSDI for $ 1,299.
You can read Jared’s short review on Cinema5d!