I've had an opportunity recently to witness two tech CEOs perform for a gathering of financial analysts: Mark Hurd of HP and Jonathan Schwartz of Sun. The contrast in management styles and vision couldn't be more striking -- a contrast made more poignant when one considers that both companies slug it out daily on the floor tiles of practically every data center in the U.S.

Hurd is Mr. Numbers. He can rattle off the size -- seemingly to the dollar -- of each of HP's approachable market segments this year and each of the next five years (geographic segmentation included). If, as an HP executive, you want to get him to buy into your new product idea, bring your best HP calculator to the meeting. Here's a well-worn quote Mr. Numbers likes to recite: "You can only manage what you can measure." I'll bet he hands out T-shirts at company picnics emblazoned with that motto.

On the other end of the spectrum is Schwartz, Mr. Evangelist. For Schwartz, Sun's Solaris is as much a religion as it is an operating system. He sees his mission as the dissemination of Solaris far and wide. The Solaris "ecosystem" is a church where devotees meet daily to worship and ply the faith. Solaris is disseminated freely, openly, fervently.

Can Mr. Evangelist do the math like Mr. Numbers? Well, consider this vignette: During a recent financial analyst Q&A session, Mr. Evangelist was asked more than twice if he had any evidence, any metrics that he could share with the audience that would support his conjecture that free dissemination of Sun intellectual property (Solaris, Java, FISH, whatever) would in fact produce downstream growth and accrue positively to Sun's bottom line. Mr. Evangelist told them more than twice that there were no such metrics because the metrics don't exist. Period. My sense is that there were few converts in the audience at the end of the session. No matter. Like the Hail Mary pass in football, you just have to believe that someone will be there to catch it and that good things will happen.

Hurd believes in numbers. Schwartz believes in believing. Both can win, although the financial analysts in the audience will naturally feel more comfortable with Mr. Numbers. Personally, I've seen both styles work, but I have two concerns. On one hand, all numbers and no vision makes Mark a dull boy. On the other, vision without corresponding results was what got Carly Fiorina fired. Schwartz faces a similar fate if he doesn't make believers out of the people whose job it is to do the math.