Being charged per gigabyte by an e-discovery software platform isn't new, but it can still be a budgetary drain for law firms that handle many large e-discovery matters.

"It would be great to figure out a way to move away from the consumption-based model," said Pillsbury Winthrop Shaw Pittman litigation special counsel Rachelle Rennagel. "I think vendors are trying to be creative, but on some level their hands are tied and on some financial level they can't absorb all that risk, especially if the case balloons."

But while the consumption-based pricing model may be disadvantageous for some large firms, it does appeal to small or inexperienced legal teams, observers said. And despite differing levels of enthusiasm, more e-discovery companies are touting and rolling out the consumption pricing option.