I use the St. Paul often when I have small groups in Munich. The location is great since it is just one stop from the Train Station and the entrance to the U-Bahn is literally right outside the front door.
The rooms are of good quality and modern enough. They aren't large, but for the price they are a great value. The street outside is not too busy, so things are relatively quiet in the evening. There is also free wireless service in the lobby and covers some of the breakfast room.
The folks at breakfast are particularly nice. They specialize in preparing your eggs just they way you like them, so be sure to ask. The entire staff here is very friendly and accommodating.More