Hi Lake,
I (and two of my friends) bought 40" EX520 during end of Oct 2011. I have simultaneously compared EX520 along with all Samsung series 5, LG 42" 3D 5700 (or 5500 - I dont exactly remember the model number now). The LG 3D TV was the one with ordinary 3D glasses which will not strain your eyes and had best refresh rate in my opinion.
To test we carried two USB pen drives with same HD/SD contents.
1. color depth, clarity, rendering - sony > LG > samsung
We watched one of the HD videos where it was shot in front of one of the walls of some fort. The wall is built with pieces of large stones blocks and glued with white mortar. Sony was spot on to render it properly and you will understand that it is a fort. LG was too good in this department. However, Samy messed it up and display was very bright in some spots (mortar) and face of the male/female characters in the video was pale/yellowish.
2. brightness, contrast - Samsung > LG > sony
Samsung was brighter than the rest. We tried to adjust video/display settings of all TVs samsung stood out. I think this is sometimes an overkill - There was video of a gentleman closeup shot where I could differentiate the face with the clean shaved (mostach/beard) upper lip, chin etc in Sony and LG but not in Samsung. It was all pale/yellowish.
3. Sound - Sony > LG > Samsung
In samsung until 40 points, volume increases after that nothing happened noticeable until 100. In Sony until 90 points, volume increases. I dont remember what was it with LG and definitely better than Samsung I suppose.
4. Media support - Samsung > LG > Sony
Sony does not support a lot - especially the MKVs, NTFS support. You are limited by connecting only upto 32GB (correct me if I am wrong) thru USB as Ext-FAT3 supports only upto 32GB.
5. Fast vidoes - LG > Sony/Samsung
Running billboards, news etc LG was better. The same when viewed on Sony/Samsung there was some drag at the end of each word.But then it has better refresh rate than Sony and Samsung. However, I did not see any difference while watching Fast&Furious and other similar action movie clips.
6. Price and offer - Samsung > Sony > LG
Diwali offers + we were buying appliances worth 3.5L - hence got very good offer on all the things we bought. Hence this parameter might not be true comparison to rate the TVs. We decided on ex520 or LG 3D and dropped samsung from the list.
I choose Sony for the following reasons:
1. My personal opinion that 3D technology (both hardware and software) is still evolving. I can wait for some more time before bringing it home.
2. The price difference after the offers for Sony ex520 and the LG was about 14k.
3. Last but not the least - I visualize TV as a viewing apparatus. A TV should do that properly, then add MKV support, NTFS support .... what else... emergency light (pun intended) etc. I mean all these can be done in various other ways - media player, HTPC etc which I anyway plan to do irrespective of features of TV because after couple of years there will someother format that might be popular that is not/cannot be supported.
4. 60k for ex520
After purchase:
1. SD and HD both are stunning - no regrets in bringing home ex520
2. Wallmounting this TV leaves very less space to connect your cables. The Samy was probably better in this department where the connecters are on the side while sony's is right behind.
Hope this helps in deciding your purchase. However, compare more than two TVs next to each other by watching the same video, adjusting TV settings etc - Since you are going to park a good 50k plus, the test drive is worth it.
) then 40".
