Garmisch to Munich Bus or Train?

I'd suggest the train.

I've always used the train on this route. It's direct, no asphalt, no traffic congestion... are you returning the same day? When's your trip? Construction on the rail line may affect train travel depending on your date of travel.

Train seems like the obvious choice. Is it a price difference thing? Maybe if the bus is a lot cheaper it's worth it. But it can't be much cheaper to really make a difference ...

Typically, I would prefer train over bus travel.
This summer there will be a lot of construction work on the rail track Munich to Garmisch.
You can see it on bahn.de when part of the journey is marked as “Bus EV” or “SEV”. That means train replacement bus.
If that is the case for your travel day I would rather go for Flixbus.

That SEV on the trip between Munich and GaP appears to end on the 14th of July (end of next week).

If you take Flixbus, the fare only covers one way on the bus. A Bayern-Ticket covers round-trip and any transit in Munich (or in Bavaria) that day.

The train comes directly into the Hbf. Flixbus uses the central bus station near the Hackerbrücke S-Bahn station.

Flixbus runs every two hours, the train every hour, but twice an hour into Munich in the morning and twice an hour from Munich in the late afternoon.

Thank you all for your responses.

Thanks for posting this, I had the exact same question! When I look at the DB Planner for my travel day, 2 August, it still shows the SEV bus. Perhaps that will change?

Since I'll be starting my day at Mittenwald, I think I will actually go by way of Innsbruck! It adds up to about 2 1/2 hours travel time, which is about the same as if I went through GaPa. FlixBus would be somewhat a bit faster, if it's on time, but I think I'll be more comfortable on the train.

Mittenwald to Innsbruck is not a bad looking train ride - 7 out of 10 scenic more or less ....