Sony TVs excel at build quality, I'm a big fan of them. The last bastion of Japan. It's a pity they don't have much presence in SA. Not tried their SMART yet, but it looks good. Sony are less likely to poorly implement it like Samsung have been known to.
Closer to the time, the best advice is to go to a dedicated AV store which has a test room, and spend an hour playing with the Sony, Samsung and LG equivalents side by side. Take 3x flash drives with the same content. Start by taking them out of Dynamic/Demo/Torch mode, set them to Movie/Cinema mode and adjust brightness, contrast, backlight etc. from there.
I think you'll be happy either way, as it's a relatively small outlay for an entry-mid range TV which are usually all on par, you might feel the time isn't worth it, fussing so much over comparing. If you like Sony, you will be happy, I have no doubt.