It is widely regarded that the DVI/HDMI is best for digital, fixed pixel displays (plasma, DLP, LCD LCOS) and does not affect the picture quality for analog CRT TVS. The reason being that there needs to be an analog conversion done either by the TV or by the DVD player, and it does not really matter which one. But since a digital TV is digital, with DVI, the picture stays digital all the way from DVD to screen. Thus producing a better picture.
Some people do say there is a difference on large screen analog displays, but I have not seen it.
About black level, a good DVD player will be able to produce true black, however, many DVD players, such as the Samsungs, cannot reach true black. That is a complaint mainly for people who can get there rooms completely dark.
Also, the HD841 does have DCDi by Faroudja, it is what does the upconversion. Check out the link I posted above, you can see the DCDi logo on the player.
Or check out this link:
http://www.samsungusa.com/images/prod/product03/b2c_l_hd841.jpg
