i have pbly 5 or 6, of them, maglite original led bulb, luxeon, diamond led with dome and side emmiter tip, sears led bulb, and another no name bulb, the only 1 i use is original maglite bulb in 2c mag with 2x18650. the rest pretty much sit in a box, they are not as bright as 4cell bulb, they draw less so they run longer. their tint varies from blueish to nasty blue
i have not seen anything recently done to inmprove on them, they had a purpose when most flashlights were using pr bulbs, now that most flashlights designed as leds from the start, and pr bulb lights are almost extinct, *(except $1-2 lights, and maglite) no reason to make them. imo