Music or Ballet - Munich or Berlin?

They are both first class. I don't think anybody but a true virtuoso would be able to discern any difference.
The important thing is that most of these shut down in the summer.

Edit - I see that the Bavarian State Opera continues to the end of July with the Munich Opera festival.
https://www.staatsoper.de/en/index.html

Berlin has 2 opera/ballet companies. Deutsche Oper Berlin, and the State Opera Berlin.
State Opera-Berlin runs through the end of June, then a run of West Side Story in July.
https://www.staatsoper-berlin.de/en/

Deutsche Oper Berlin runs pretty much through the end of June and restarts August 22
https://www.deutscheoperberlin.de/en_EN/calendar

As in the USA, summer is not the best time to find large indoor musical events. In addition, major cities have devoted followings and it can be very difficult to get tickets, unless you buy months in advance. (At least that's relatively easy on the Internet, but you have to make sure you have found the legitimate source of real, first-issue tickets.)

Although there has been debate about how many opera companies one city can support, Berlin still has multiple opera companies. Some viewers don't care for the modernistic Philharmonie building in Berlin. But I think Berlin has a slight edge over Munich. (I haven't visited BOTH of those cities on one trip to Germany, because it's such a culturally rich country.) We once settled for a chamber concert in the smaller Berlin Phil room (which is plenty big) on our arrival day, because that's the only way we could get a concert that week! It was a struggle to stay awake, of course!

Another option you can consider is seeking out summer festivals. It's not near either city, but because WE missed it, I noticed that distant cities like Schwerin can have major arts festivals at the height of summer. When I've wanted to see a particular venue, like the Marmoreean Saale (sp.!) in Salzburg or Smetana Concert Hall in Prague, I've been happy to settle for short "tourist concerts."

Between the two cities, absolutely Berlin...three different symphony orchestras in Berlin....bumped into a summer open air concert (Konzert im Freien) on a Sunday ca noon a few years back in the Gendarmen area, totally by accident, just followed the sound of the music.

It was the Berliner Sinfonie conducted by S Rattle (sp ?).

As expected they played Beethoven...utter fantastic, captivating, mesmerizing, as I joined everyone else standing there and listening. Rattle addressed the audience afterwards in German too, absolutely one the highlights of that trip.

If you enjoy the ballet, go to the ballet. If you don't, go the concert.

Good , thanks for the information...stand corrected.

I think Fred may have intended to refer to the multi-year controversy over whether the city of Berlin can afford to continue to have THREE OPERA houses in operation. One problem is that the Komishche Oper was behind the Wall, and it would be an insult to the ... er ... new citizens to pick their opera house to close down. As an American, it's startling to hear about a ... Social Democracy ... that is coming to believe that there are limits to what the state can do for its people! Although presumably, interest in opera is suffering gradual cultural decline there too, if at a lower slope rate.

Admittedly I thought that Berlin had 3 symphony orchestras which is incorrect and inaccurate, was not referring to the opera houses.

I agree with MarkK that Berlin has the edge. Apart from Berliner Philharmoniker (one of the best symphony orchestras in the world) I would also like to mention Akademie für Alte Musik for baroque music.