I've been a long-time proponent of NVidia cards (For close to a decade) and have bought at least 30 of them for projects and upgrades and the like.
For the past 5 years, I have been struggling with the overscan issue when using the HDMI connection on my Pioneer Elite plasma. I was never able to get it to work properly as the TV has no zooming/scan compensation capability. I used all of the options in xorg.conf in many different combinations without success. Either I had to use VGA or loose large parts of the desktop.
Last night, I used an ATI Radeon for the first time and using it's Catalyst programin Ubuntu, it was as simple as sliding a bar right and left to adjust the oversan (and the underscan). Now for the first time ever, I am using HDMI with my computer and getting the correct picture at 1080i. It is bitter sweet.
The main dissapointment is that customers have been complaining about this problem for at least 5 years and NVidia has not been responsive on it. Yet, it shouldn't be a dificult piece of code to put into place. Have I given up on NVidia? Not entirely. But for my current HTPC, yes.