From painful experience:
Sony – Superb picture, low lag for gaming.
Everything else is awful – interface, remote, build quality.
It even has to ‘warm up’ – the software takes about a minute to sort itself out every time you turn it on, and whilst it’s doing so, you can’t change channel or use the menu.
Apparently Sony are stopping making TV’s shortly.
Feels like they gave up on them a while ago.
LG – picture just slightly worse than the Sony in pretty much every respect.
Everything else fine.
Really easy to set up with the built in calibration software.
Panasonic – best balance.
Picture nearly as good as the Sony, but interface is really good, very comprehensive but easy to use.
Seemed very solid too.
Ended up with the Sony after demoing loads, wish I’d gone with the Panasonic tbh.