I know this is a little late--But I just got back from vacation in Milwaukee and attended the first game of the series up there (the Josh Fogg start)--a few thoughts:
1. The atmosphere in the parking lot is awesome. Everyone's tailgating, throwing baseballs back and forth and drinking (lots of) beer. So different from Cincy--Just like a college football game.
2. The stadium is a good place to watch a game, but a little boring. From the outside it looks a little alien. Inside, there's pretty much no connection to baseball history/the city other than the yount/molitor jerseys. Bernie the Brewer goes down a long slide from the upper deck to the lower one everytime the Brewers do something good, but that's it. Not much aesthetically. At least GAB has the river.
3. I've been to games in five cities other than Cincinnati (all while wearing my Reds hat/jersey). Milwaukee is the ONLY place where I've really been heckled. Basically all the way from the parking lot (and then throughout the game) Brewers fans were yelling things like "Cincinnati sucks"---Wasn't too impressed with the fans in that regard.
4. Overall, Miller Park and the Brewers experience was not that great--PNC in Pittsburgh is still my favorite--GAB is definitely a cut above Miller.