Personally, I don't think the beer will be effected--at least initially. Anheuser Busch has a habit of acquiring brewers not necessarily to turn all their beers into more diluted corn water, but to acquire the fan base of said beers (Rolling Rock, Grupo Modelo, Tsingtao). That said, there are plenty of AB-InBev's (or MillerCoors') acquisitions which have declined over the years, no doubt from pressure to cheapen their products to appeal to a larger audience. And seeing brewmaster Greg Hall step down doesn't instill me with hope that the beers will remain free of the corporate giant's influence.
So will I keep drinking the beer? Not that I was a huge Goose Island consumer to begin with; Bourbon County Stout was really the only beer of theirs I drank with any consistency. In the end though, I think I'll pass next time. The beer may well be every bit as good as ever, but the simple fact is that I don't have the time or the money to drink every beer I would like. And there are so many good craft beers out there waiting to be drank. The fact that Goose Island is owned by Anheuser Busch-InBev is the only reason I need to pass by the Bourbon County and pick up a Founder's Kentucky Breakfast Stout, or an Espresso Oak Aged Yeti, or an Odell Bourbon Barrel Stout, or a Schlafly Barrel Aged Imperial Stout... the list goes on.
People will say "beer is business", and accept things like this as an inevitability. A product is being produced, and money must be made. But if we want craft beer to be taken seriously, to be recognized as the great step above BudMillerCoors macro lagers that it is, the money can never be the first consideration of the brewery owners. Or the malt and hop farmers, the maltsters, the brewers, the distributors, the servers, or the consumers. Brewing is an art, and beer is an art form. Artists get paid too, but they're not (or shouldn't be) in it for the money.
