The panel produces exceptional visual quality and was the reason why I bought it, along with HDMI and USB ports, it was an easy choice.
I have never tested the built-in speakers, so I can't comment on their quality.
After almost 7 years I've never had an issue with my 46" variant of this TV.
I paid $2200 AUD in March 2010.

Paid top dollar for a 55" LED Samsung television on 26th June 2009. 3 years later the panel needs to be replaced, will hesitate replacing with a Samsung...............Also living in country Victoria it was hard to find anyone interested in looking at the problem. Emailed Samsung who said update the firmware software which was totally useless and a waste of time. Would advise others to look at support if buying Samsung.......!
Initially top of the market LED, 6 star rating was the main feature of buying
Only 3 years later having to replace it!