When I interviewed CEO Robert Shaw of SIEM provider ArcSight several months back, he told me he didn't believe in mergers and acquisitions because of what they do to employee morale and product innovation.

Independent companies, he said, are "driven by a small cadre of people who are really motivated and evangelized in their area, and their intent is on creating something great. But once they get bought and they can't control the destiny of their baby anymore, they move on."

Shaw and I didn't discuss the possibility of ArcSight IPO'ing, but maybe we should have. After all, while the CEO stayed true to his word about his 7-year-old firm not getting bought out, it would be interesting to know how going public may affect workers and customers there.

John Pescatore of Gartner thinks going public has more of a detrimental effect on companies than if they are acquired.

"When they go public, it diverts so much of their attention away from the customer and focuses so much on Wall Street stock analysts and projections and closing [sales] in the quarter [to meet projections]," he said. "Going IPO usually is more financially lucrative to the management team, not so much to the rest of the company. And it definitely takes a company off the customer and points them to Yahoo! Finance to watch the stock every day."

The positive of going public? A huge "war chest" to invest in the company.

For successful companies, it's going to be one or the other: acquisition or IPO. So far, given the mass consolidation within the IT security space, M&A is winning out.

As Pescatore told me, why deal with the hassle of going public and having to meet Wall Street forecasts when Cisco or HP or Symantec or IBM is knocking on the door, willing to pay millions?

But, then again, some people are Robert Shaw.