IF you care about 3D, the Pan UT50 series offers it, whereas the LG does not.
Beyond that, this is a tough choice, given same price & larger panel for the LG.
Given CostCos excellent 90-day return policy, I would opt for the LG: it received a very good review from CR.
As BillP already noted, viewing distance is important - as is YOUR Normal Program Material.
If you sit LESS than 9 feet from the display, and/or Primarily view Non-Blu-Ray programming, the (Slightly) smaller panel might serve you better.
At 10 feet or out, or for blu-rays, would go with the 60.