Phil,
I am using a Crystalio scaler, sdi sky box and sdi philips 963 dvd player.
This is going abck top the screen with DVI and RGBhv to the 5 bnc board.
OK I had a bit of a play last night with the DVI input, set it up with the Pixel magic disc to get 1:1 mapping and with the preinstalled settings for the 50PHD6 that is built into the Crystalio, this is obviously at 60Hz, and all I had to do was adjust the position and cloock phase. Easy!
I spent just under an hour last night trying to get the DVI to look as good as RGBhv, I just couldn't do it. Black detail was lost compared to the RGB, and the whites seemed to look more digital, that sort of annoying tizz you get on cheaper plasmas.
As I was using the Crystalio I could switch between RGBhv and DVI really quickly and it was obvious the analogue is so much better than DVI.
On the Samsung LCD I tried the DVI was so much better than analogue, but I still think that hdmi/dvi is a crappy interface.
I am sure the people who designed HDMI sat there and thought "lets come up with an all in one digital solution that includes hi-def copy protection" and not "Let's come up with a new interface that beats analogue at every level quality wise!".
I quickly tried 720p at 50Hz and didn't have any joy with that, but to be honest by that point I had lost all interest in the digital input so didn't persue past the preset 720p/50 built into the scaler. Same with 1080i @ 50Hz.
For now I Just don't think anthing can beat the analogue inputs, they are that good on the Panny, also lack of native res makes the digital inputs useless anyway, the difference between getting it 1:1 mapped and not quite (ie inputting native but not adjusting the size so it snaps in) is very apparent.