I recently upgraded from a 40" Samsung LCD to a Panasonic P50ST50 and have been quite pleased with the improvement in picture quality. The framerate processing that converts 24p to 60Hz is especially impressive--looks much better than the "native" 24Hz mode on my old LCD.
My only quibble with the Panasonic Plasma is the buzz it generates in very bright scenes. GF doesn't even notice it, but it irritates me occasionally (I'm quite sensitive to electronics noise).
6600K @4.2, Asus Z170I Pro, EVGA 1070 SC ACX, 16GB Corsair DDR4-3000, 256GB Samsung 950 Pro, 480GB Sandisk Extreme Pro, Corsair SF-450 PSU, Silverstone ML08B, Scythe Big Shuriken 2, Realforce 87u 55g, G400s, X-star DP2710@100Hz, Audioengine D1, Sennheiser HD598