I reckon the LED Samsung has probably one of, if not the best High Def pictures I have ever seen, it is unbelievable. However; SD pictures are below par in my opinion, so much so, it would probably put me off buying one.
The Philips Essence has probably the best all round picture (out of all the LCD's) but is really expensive and is only available in 42" (as far as im aware). I must say I am a big fan of Philips and although they can be expensive I do think they are sometimes under rated a bit. I have a 3 year old Philips 42" LCD and was seriously considering replacing it this year as I want a bigger set but I honestly cannot find a TV with a better SD picture; I am therefore holding on to my cash for the time being as I cannot stretch to a Kuro.
I know the Pana's are good but they dont blow me away and I do not see a massive difference when compared to my Philips ... maybe next year will bring better things; im quite happy with my current set so theres no rush.
As for the original question, out of them two, I would probably buy the Samsung if it was my money; but out of all the current sets I would probably go for the soon to be released panasonic V10. Obviously the Pioneer is the best set you can buy, but that costs £2k plus and out of reach for alot of people.