Figured warranty and/or RVS (Rotation Vibration Safeguard) would have been mentioned, as well.

Consider warranty to be an OEM's confidence in their device. Bit on RVS, http://www.zdnet.com/blog/storage/bad-bad-bad-vibrations/896

Cost math on price can be interesting. As an example, a device getting twice the value out of a set of Red drives vs RE drives. SMBs would be more of the mindset to take the lowest price (yeah, yeah, not enterprise).