The other crypts I toured don't allow photography, so you'll have to take my words as enough.
St. Michael's Church is near the Imperial Apartments, the Hofburg and many of the other Habsburg buildings in Vienna's center. It has one of the most extensive crypts of any church.
First a little information. The Habsburgs were mummified for burial. Thus, their vital parts had to be removed.
Their bodies are buried in the Kaisergruft, hearts in containers in the St. Augustine church (see the cannisters in the poster below),
and their viscera (lungs, intestines, liver, etc.) in the crypt at St. Stephens.
The tour of the crypt in St. Michael's church was excellent. It was given in English and German (like the one in St. Stephens) by a very enthusiastic and knowledgeable guide. We viewed 2 coffins with mummies (very well-preserved) in them, lots of ossuaries and saw galleries with lots of beautifully decorated wooden caskets. There is continuing renovation going on down below, with a majority of the galleries still walled off from centuries ago.
One musical person of note is buried in St. Michael's -- Pietro Metastasio (one of Mozart's librettists).
I later toured the crypt at St. Stephens and tried to go to the one at St. Augustine's church, but it was only available for tours after the Sunday services.
While morbid, I found these trips to be fascinating and certainly something we don't have here in the United States.