Yup, the LG version (actually their panel). The Sony version is still $25K (retail), and not large dealer margins. I've played with both (LG/Sony), and have seen the Sammy, but own the Sony version. I put it in my kids media room, they use it for gaming. I recently allowed Sony to do the new HDCP/HDMI upgrade and swap out the 4K Dell Media Player for the new Sony 4K Media Player, works great, but we had more 4K content on the Dell.
Back to the OP's question, I had a difficult time deciding between the Sony and Samsung, but in the end I couldn't justify the additional $20K for the Samsung (The cost of the Sony was already ridiculous).
I have never done any real testing, or side-by-side comparison, so difficult to say one is better than the other. My observations are therefore mostly subjective. I opted for the Sony 84" over the Samsung 85" primarily because of cost, so your "$5,000 more" question is relevant. I'm not sure what the number would need to be to get me to move to the Samsung because both displays offer an excellent picture. I didn't buy into the 4K marketing, but I did factor in 4K because of the screen size, and because all of the other 80"+ screens had image degradation at close seating.
Would I have taken the Samsung for $10K more, "no," at $5k more, not sure, maybe. If it were only a couple thousand more, then "yes," it would be in the kids media room.