My original set was a 55H7150 with the TS01 panel. (Build date Nov. 2014) I questioned the corner flashlighting and viewing angle, so I temporarily held onto the original while I received 2 replacements, both of which had US02 panels. (Build dates Dec. 2014, Jan. 2015) In my opinion there was very little difference with the PQ. The US02 panels had slightly brighter corner flashlighting, but in a smaller area than the TS01. However both of the replacements had cosmetic issues (which I attributed to late in the model year production issues), so I decided to keep the original. Hope this helps.Yes, two different TVs of the exact same model can have completely different characteristics. It all depends on which one you get. If you look at the label on the back of the TV, what is the "version" of the new one you got? The exact TV you are discussing (46 inch H7150) can come in 2 different versions (that I am aware of). It can have either the TS01 panel or the US02 panel.
I don't think anyone has ever answered what the exact difference is between the TS01 and US02. Both versions are made by Samsung, and both the 46 and 55 started out with just TS01. So it is quite possible your first TV had one, and the replacement, even though it is the exact same model number, had the other.
In fact I would raise that as a question. What is the exact difference between those two versions? I've heard the answer "Don't worry about it", but there is obviously something different by the numbers.