We stayed at Louis Hotel for six nights on vacation and overall had a very good experience. In reading others reviewers' reactions to the property, I can only say that if you're an American used to staying in Marriotts, then this isn't the hotel for you. It's very well designed and the rooms reflect this; hardwood floors, cool furniture and things you don't find everywhere (such as a closet that pulls out of the wall). The views over the Viktualienmarkt are charming and we spent many an hour parked in front of the doors that open out onto a Juliette balcony, soaking up the sun, sights, sounds and smells. Yes, you will hear tons of church bells and yes, you will hear noise from the marketplace vendors setting up below but if this is bothersome then perhaps you should have gone to Des Moines and not Europe.
We found service to be mostly competent and friendly, ranging from dining room servers who after the first day knew I wanted cappucinos without having to ask, to a front-desk clerk who made a number of arrangements for us. Our one true negative service experience was a call to room service for some kind of a cheese plate of something we could have with wine in our room before dinner -- the response was "we don't have anything like that. click." Minor things like this reminded us we were in a hotel that, while fine in all regards, is trying to play a bit out of its league.
Also in the category of minorly annoying was that the walk-in showers have no grab bars or shelf to put anything on -- which creates kind of an odd and slightly unsettling shower experience. The heated floors are a nice touch, however. In this same category is the fact that complimentary water was never replaced -- it appeared that we got two small bottles for an entire six-night stay and they were never replenished.
We know the hotel scene in Munich fairly well and still feel confident that this is an excellent choice for a traveler who appreciates design and a good location, but doesn't expect Four Seasons-like pampering and service.