Is it clear water that's leaking out, or buttermilk? Your recipe doesn't have
the clarifying steps that mine does. Mine starts out the same (2 cups cream) but says process until the butter comes together in large grainy globs (about a minute after the processor sound changes from whirring to sloshing). Then you drain off the buttermilk and add 1/2 cup ice cold water. Process a couple of seconds until the water is cloudy. Drain it off and repeat until the water stays clear, which indicates that all the buttermilk has been washed from the butter.
Not sure, though, if that affects the flavor, which would, as you say, depend on the quality of the cream. If you have to use supermarket brands, avoid ultrapasteurized cream; it's really hard to make butter with it.