OLED is very good but it's still really new tech and has its niggles. You cannot really compare say a 15th generation plasma to a 1st or 2nd generation OLED. it's too new.
I would wait for at least the 5th or 6th gen panels.
the LG OLED i saw was fine, miles better than my very good Plasma, dont forget the Plasma is far from perfect it has quite a few faults.
i'd say either get the best current OLED, or the next generation due out soon, because you wont be disapointed.
the Panny Plasma is too old now, yes it's better than LEDs, but nowhere near as good as an OLED, the difference between an OLED on 4K and a Panny on 1080p is massive