For as bad as the NSA and GCHQ programs are/were, there is at least some reasonable way to restrict them from damage.
For corporations, there's effectively no limit to the amount of damage they can do.
Yes, government-level info gathering can result in some pretty awful things - prison, in the least, for a limited number of people. A breakdown in trust of government as a whole, however, is probably the worst thing such pervasive intrusion can cause. BUT, we have relatively fast control over this kind of behavior. We (citizens) simply pitch a fit to our representatives, and a loud enough fit (aided hopefully by expose from people like Edward Snowden) gets results rather quickly (weeks or months). The NSA policies and practices are changing, as we speak. In the end, government is responsible to the people, and if enough of society says to change the policy, it gets changed.
Compare that to information gathering and use by a company. It's regulated by? Well, if you're lucky, the government. If not, then by nobody. And there's no oversight at all. They pretty much can do whatever they want with it, and there's virtually nothing the average citizen can do about it, even in large numbers. The company's management controls the data, and they're pretty much completely insulated from outside influence. Not even stockholders have much say here. And there's virtually no penalty for them misusing it. Take the Target debit card leak. It's a very temporary, minor PR problem. They're not on the hook for any damage they cause those people by mishandling their info. And that's a minor case - think of all the places where corporations buy and sell info for no benefit of the individual, profit from it, and usually to the detriment of the individual.
I'm in no way saying that government info gathering is good - we need to keep a close eye on it at all times. However, corporate information gathering and trading is infinitely more damaging to society, especially in unregulated places such as the USA. At least we have a reasonably ability to correct government oversteps - when was the last time you saw a company penalized (or heck, even substantially change its policies) due to mishandling of individual data?
Thanks, but I'll trust a representative government long before I'll trust a private, for-profit entity.