The more attachment-heavy your company is, the more a caching appliance makes sense in terms of ROI. If you have complex discovery and compliance needs, you will want to consider using an appliance in concert with e-mail archival software. Both of these product categories are growing, with good reason: Another recent Osterman Research study found that 59 percent of enterprises call messaging storage growth a serious problem. And messaging storage needs are growing at a clip of about 35 percent per year, according to Michael Osterman, principal of Osterman Research.

What's Danback's advice to other CIOs about e-mail appliances? "Look at what could go wrong with your e-mail and do something about it now. So you don’t get yourself in a situation where you have proprietary or secret information in the public mail," he says.

Also, he says, be choosy about the number of non-Microsoft products you add to your Exchange/Outlook environment. "The more features you add that are not Microsoft, the more chance you can create disruption," he says, noting that one reason he likes the Accellion box is he's had no issues other than initial setup tweaks during testing.

Eventually, Danback says, he envisions Microsoft itself buying a company like Accellion and bundling such functionality into packages for enterprise customers. "It just makes a whole lot of sense," he says.

Until then, he's sticking with his ticket out of attachment hell.