Only had the time to play with the Optimus G, I couldn't compare with the others. I was able to try a S III, but they were locked to the table, so I couldn't test the feeling in my hand. The HTC wasn't available for demonstration, I couldn't test the UI.
My impressions with the LG were quite favorable. Wasn't impressed by the 8MP camera (pictures looked a bit washed), but I liked the UI in general, more than TouchWiz. The phone reacted quickly and smoothly. Really liked the size and feel of the device, except maybe for the sharp edges around the phone. I'll be putting it in a case anyway. No expandable storage, comes with 32GB. Phone is $129 with a 3-year contract.
LG or not, it's a tempting phone.
The Samsung is $159 for the 16GB with a 3-year contract, but it sometimes drop to $0. No word on the One X+, but the regular One X is $99.
Waiting for potential Black Friday sales to take a decision.