These are primarily the WS2811, WS2812, WS2812B or NeoPixel series of LED's.

• These are inexpensive compared to 4 pin strips.
• You can use several pins to drive multiple strips with them.
• The disadvantage is that FastLED disables interrupts, so you can't use libraries that rely on interrupts (such as IR remote) at the same time on an 8 bit AVR.

These are primarily WS2801, LPD8806, APA102 or DotStar series of LED's.

• The advantage of these is that FastLED doesn't disable interrupts, so you can use 3rd party libraries that require interrupts.
• In addition, these LED strips support a much higher refresh rate and can be used in POV applications.
• FastLED doesn't support multiple strips though.