I think the Sony may be a slightly better set, but if it were my money I would buy the Samsung and pocket the extra $600. That Samsung is a very solid set.
If you're not concerned about the money, then I would suggest comparing the Sony to the Samsung LN52A850 which is similar in price to the Sony.
Both are nice displays. I would buy based on the retail policies of the dealer, pricing, warrranty policies, and your desire for color accuracy (with the Samsung being more capable of being made more accurate).