Samsung PN51D550 vs LG 50pz750 HELP!!!

Hello everybody. I am about to purchase my first 3dtv and I need some serious help. I have narrowed down my choices between the Samsung PN51D550 and the LG 50pz750. I am only in the market to get one of these to watch 3d movies and play 3d games. The Samsung is 200 dollars cheaper on amazon than the LG. Does any one know which one is best? I don't really care about internet apps since my blu-ray player will have those things. The major things I am looking for in one of these tvs is:

strong black levels and minimal cross-talk.

I have read many great reviews about the Samsung and have not been able to find much of anything about the new LG. I have been saving money for over a year as I am a broke college student and I am ready to make my purchase, finally! Really what I would like to ask you experts out there is which one is better and will spending the extra 200 dollars on the LG make that much of a difference? The only difference I see is the LG has internet apps, a magic remote, and THX certified display. Is the THX display that much better than a normal display? What exactly does the THX certification mean?

Thanks!
1 more thing! What is the best way to break in one of these types of tvs?

 

I advance you choose another 3D TV.
In our lab, these two get very low score in long-time playing. The brightness of the display panel of D550 and pz750 series will fall down after 1500hr.
At that time, the effect of the 3D video will obviously fall down.