If you are In Milwaukee its worth the trip.
Start off at the Visitors Center get free tickets for the tour, gotta be 21 to drink, did I mention FREE samples of beer, try 1855 Lager only available at Miller Brewing Co.
Watch short presentation, and be ready to walk, walk some more, up down stairs. OK note to anyone who is disabled , my tour experience was shortlived because of handicap accessibility, if you cant use stairs go straight to beer sampling, and by the way, restrooms are cramped and not exactly accessible at the Beer Garden and at the Miller Inn.
Brewery is picturesque, you can take great pictures, learn something about brewing process, definitely something to do for an hour, yes its worth the visit and its free.