This tv has a better picture and sound than a Vizio I am returning. I think it is a great value for the price. The picture is very good and can be adjusted with a number of settings - only thing missing is back light level. However, the black level is very respectable, and needed only a slight tinkering on brightness, contrast and color level to achieve a very good picture.
Sound is very good through headphones. There are bass and treble controls, or even equalizer that can be custom set.
One cannot expect high quality sound out of the small speakers in these smaller tv's
I cannot yet comment on the life expectancy of this tv - I will amend as time goes on if needed.
I've read a couple of reviews on this TV stating that they die within 6 months to a year. I purchased mine in April or May of 2011, and it's probably got the best picture out of the three LED TV's that I have. The others are a Sharp and an LG. I have not had any issues with intermittent picture or sound. I have not noticed the quality diminish, nor experienced any random problematic occurrences.
Overall it has been a great TV and I would recommend it to anyone.