Too early to tell on longevity. I've seen claims of the same vs CCFL, or more. One truth is that the LED's are less susceptible to dimming and burnout than a CCFL, so they should keep brightness longer( or lose it slower than CCFL). The back lit sets also allow for much better blacks. I bought a 3yr in home from Square Trade, just in case.

Since it is still an LCD, just a different type of back light, I'm sure it could have dead pixels.