Enterprise for max reliability
green etc for low power, but not great performance as it low speed etc, ok for data but warranty is no where near as good as Enterprise class.
GreenPower technology, these drives are designed to deliver power savings as the primary attribute. so no great speed, can be 5400
WD touted the following main points for red drives
Less aggressive head parking (no IntelliPark feature)
Configurable Time Limited Error Recovery (TLER), with a default of 7 seconds
IntelliPower disk rotation speeds (comparable to Green drives)
Vibration reduction mechanism in hardware
WD Red is the only hard drive designed for NAS systems, The drives are designed and extensively tested for compatibility in the unique 24x7 operating environment and demanding system requirements of home and small office NAS. copy pated this, yes it looks like these are better, tbh i'd still go for these or Enterprise as thats the next level
black being the standard ones for most drive types
Enterprise offers reliable storage for high capacity servers and storage arrays in a minimal footprint, plus a lot better warranty, made for long term use and every day 24/7 on and access etc
so first choice for me would be Enterprise
2nd go red,
third go green, then normal