The issue with text on OLED panels is typically due to the sub pixel layout, they tend to use different sub pixel layouts to traditional monitors which causes issues with subpixel rendering and can make text look blurry or have color fringing.

However, recently you can now get OLED panels from LG with RGB stripe sub pixel layouts (matching traditional monitors) which eliminates this problem and text should be just as good as an non-OLED display.