There is a review of one version of the Dell Studio Hybrid here -
PC Pro: Product Reviews: Dell Studio Hybrid
The problem is going to be the low-powered integrated graphics, which don't have much in the way of hardware acceleration for h.264 decode and de-interlacing. To get high-quality pixel-adaptive hardware deinterlacing for HD, you need to be looking at ATi HD4350/HD3650, nVidia 8600GT/9500GT and upwards.
I don't currently have off-air HD, but I play interlaced HD (1440 x 1080i MPEG-2) camcorder footage in MP - I recently had to upgrade from an HD3450 to 9500GT to get better deinterlacing (the 3450 would only do 'bob' deinterlacing at HD) - it looks fabulous now on a 1080p TV
Tony