I want to buy sony 40" LED. I'm unable to decide between EX520 and EX710. I was told in a showroom that EX710 has got some backlight problem and sony stopped releasing EX710. is that true ?

I was also told that there is only difference between EX710 and EX520 is motion flow feature. in EX710 its 100hz and in EX520 its 60Hz is that only difference or any other?

I compared above 2 models in a showroom and found pale colours in EX520.

pl advice me which one to choose ? I'm planning to buy it in a week days time.