The Samsung 8000 is typically compared to the VT series from Panasonic, and while the VT series from Panny has better blacks, it does not have better color. The 7000 series from Samsung, from what I've read, has the same glass and video processing in it, but doesn't have as many 'Smart' features and doesn't have the anit-glare coating, which some people claimed would separate from the glass.
Most reviewers have said that the 7000/8000 series from Samsung is second only to the VT Panasonic series, which means that for similar, or less money than the Panasonic GT series, you get higher overall image quality.
That said, I think Panasonic builds a more robust panel which is less likely to have long term issues. But, the Samsung provides a solid product I believe in their upper end models (6000+ series). Unfortunately, it seems like these series are a fair bit pricier than what you are looking at, and at that price, I think Panasonic build quality is well worth it.
