The iPhone 6 - 8 copy LCD screen quality varies greatly. Most repairers fit the cheapest thicker outcell replacement screen with poor colour gamut and touch control, inferior IC, flex cables and connectors. CCR offer standard, premium and the advanced quality incell LCD with original IC. The thinner incell displays are regarded as good as or better then original and have the touch film incorporated in the display making touch function better and much harder to fail when the front glass is cracked.
Since the iPhone X Apple started using Organic Light Emitting Diode (OLED) displays replacing Liquid Crystal Displays (LCD). The XR is an exception and still uses an LCD screen. Original OLED screens are flexible so much harder to damage the actual display when the glass is cracked. Copy Rigid or Hard OLED will be damaged much easier. Copy screens come in LCD (replacing OLED in X, XS, XS Max for cheaper price), hard OLED and flexible OLED. CRR do not offer the hard OLED as they are damaged easily.
So please choose your screen based on quality and budget.