Yeah it's a good idea to check them out if you can. Your eyes will tell you mostly what you need to know. You could try
Rtings.com - Find your TV for reviews. I like that they post some somewhat objective results like contrast and black/gray uniformity ratings. FWIW, Consumer Reports rated the LG at 67 and the 50" Samsung model at 68 (74 is high score). My understanding is that LGs tend to have a larger viewing angle before PQ goes significantly down if that's important to you.
I've been doing a lot of research lately as I'm looking to replace a very small LCD set. I didn't pull the trigger fast enough on the Samsung F8500 plasma that I wanted, so now looking at the LEDs. I can't wait until the OLEDs to get better and cheaper.