Once you've got the group assembled, give them the latitude to critique anything you've done. Don't feel threatened by their comments. These are the things your staff is either too scared to say or too immersed in the culture to recognize. Besides, the same loyalists will be the first to defend your honor if an outsider were to criticize the company. Then there's the unintended side effect from tools like these.
Customers suddenly feel empowered.
You aren't just taking their money, but asking their opinion. All things being equal between two companies, I'd feel much more inclined to give my business to the one that listens to me. And, over time, I'd bear with the company through tough times because I'd feel like I had a stake in the turnaround. Those are benefits that traditional research won't provide. And it's all there for the taking, if you'll just ask.