I'd suggest asking for List price for this kind of article. It used to be what vendors all put in their press releases. Between discounting factors in price negotiation and data reduction factors (parity vs. mirroring, dedupe, compression, thin, snap/clone versioning, etc.) and what math is claimed, the real $/GB for a customer can still vary widely. But if vendors do all this math for you as in this kind of article, you never know what you're really starting from. Better to separate the simple, raw $/GB at list and then work through the rest of the bets separately for different deployment choices.