Blake Williams on where to look for product feedback:
While you should listen closely to criticism from friends, you should take most compliments with a grain, nay, large shaker of salt. Take them for what they are: support and validation that you are a friend. The same goes for more conventional, standardized user testing, too. The average person often just doesn't want to hurt your feelings, even when they're repeatedly told they're anonymous and getting paid to do so.
In fact, most people, even if they're not friends, will give you positive feedback when asked face-to-face. "Your product is good" is not a reliable metric. Measure usage and conversion goals instead. Some inspiration here. Alternatively, ask a community of opinionated jerks for their opinions here.
At the same time, don't take this as an excuse to not seek feedback from your friends. Seek feedback from every source you can get your grubby paws on, especially if this is your first startup. Lack of feedback kills.