Well he's talking resoloution. Considering DVDs are only 720x480 resolotion (if they're 1.78:1 not some of the other formats which are acutally lower resoloution generally) and the 30" Cinema Display goes to 2560x1600. This means the DVD will have to be scaled to this resoloution. This is the heart of the problem for most DVDs on high resoloution monitors. The process by which the image is scaled bump. burn, dither, interpolated, or any of the myriad others is what's responsible for the quality at the end when you look at it. To say that the DVD will or won't look good on the 30" display assumes that the scaling process will be good/bad. To say that it won't be as good as a DLP/Plasma is incorrect. It will be technically better, but because of the fact that DLP/Plasma TVs are larger, you have to stay farther away from them to take in the picture. This means that your EYE will blur some image segments and make the picture "seem" better. In actuality the resolotion of any DLP before this latest generation will most likely be 1280x720 or lower, thereby you can see the 30" display at 2560x1600 smokes it. If we were talking 1080i video the Cinema series would further show its resoloution advantages because 1080i/p will be shown at 1920x1080. This means that the DLP/Plasma will have to down convert the image for playback whereas the Cinema Series set will not.
Been selling TVs and other consumer electronics for 7 years now (including that 60" Samsung DLP) it's a terribly confusing situation, but if you want your stuff to look absolutely primo on your computer what you need is a better scaler. I haven't attempted to scale any vids on a mac yet. My media center pc is where I play all my DVDs because I have it set to perform several operations (also known as postprocessing) while it's converting the picture to my projector's native 1920X1080 resoloution.
If you'd like more info about what's going on you can start
here
And also
here
