Indy - did you mean LED backlight?
Hard to tell from the links. Samsung claims a 30% higher contrast ratio but you can't trust ratings. It all depends on how they are measured and samsung does not specify what standard it used.
The Sony write up is so much advertising bull, no technical data.
The only way to tell is to find a store with both and view them with the same program running. You also need to actually see how much glare they have. Some brands I looked at had horribleglare from reflections.
Try your local walmart for comparison viewing. They have sony, smasung, sanyo, polaroid and some new brands. And best of all they don't cheat like Best Buy and Circuit City and display the sets under reduced lighting. The sets get the same lighting as the rest of the store.
Update
I just read through the 212 reviews on the 2 sets... Do you have a third choice in mind?
Cons:
The Samsung has several technical issues and many had to have on site upgrades done. Getting the latest firmwar is important.
Neither Samsung or Sony support HD picture in picture.
The Samsung speakers got slammed repeatedly as junk.
The sony did not have as many repairs, but, the sony service and warantee support sucked.
The Sony display has issues with clouding, an LCD issue less commented on with Samsung.
There were the usual LCD Panel complaints about blurring in standard definition and in fast motion.
Image quality still does not match a good CRT TV.
The Samsung runs hot, but then any big screen is going to.
PROs:
Samsung service was excellent.
Only one dead pixel complaint out of 212 reviews.
Picture quality was generally considered good on both sets, except for the Sony clouding.
Good luck. I'm planning on getting a 40 inch for xmas this year. Report back on your results.