Is Google Analytics enough? I think it completely depends on what your campaign metrics are and what your definition of success is. If all you’re concerned with is tracking web metrics – visits, source, views, downloads… – Analytics is enough. Using the campaign tracking functionalities, you can get surprisingly granular campaign metrics.
However, if your metrics for success are more related to contacts, prospects, subscriptions, and leads, you really need to augment Analytics with systems that deliver Lead Nurturing and Leads Management functionality. Raw numbers aren’t enough. You have to capture a contact and tie those metrics to that specific individual.
But to get back to the question, yes and no. I think Google Analytics is enough for some companies, but not for others. For many companies, I don’t think there is a whole lot of argument for investing in enterprise level systems like Webtrends or Omniture. For what they are and what they give you, the cost (initial +ongoing) can’t be justified when reasonable, competitive solutions are free. It would take a hugely significant increase in conversions to justify that kind of hit to a company’s operating margins – particularly for the small-to-medium companies. I don’t think analytics software alone can deliver that.