Exactly, to say an SSD is 8x the cost of a hard drive, or even 2x the cost, is missing the point. Even an expensive SSD is _cheaper_ than a HD on an IOPs to IO

Exactly, to say an SSD is 8x the cost of a hard drive, or even 2x the cost, is missing the point. Even an expensive SSD is _cheaper_ than a HD on an IOPs to IOPs comparison, and IOPs is what matters to most people.