Our experience at Haus Gassner was mixed. Some good but mostly bad.
On the positive side -the location of Haus Gassner is excellent as it is only a short bus ride into the Old City of Salzburg, with a bus stop only about 150m from the Haus.
The rooms are full of light and are airy. However, thats where it ends...
As we were traveling in the summer and wanted to avoid living in air-conditioning, we opened the window on our first night to only have the room literally inundated with mosquitoes. However, this wasn't too hard to get rid of as we had some mosquito repellent for some and the others were taken care of by the notice and significant cobwebs and daddy-long-legs spiders in the corners of the room.
Our bed was on a bit of a slope so with your head effectively downhill, you'd be sleeping with the blood pressure in your head slightly higher - this isn't great for a restful night's sleep. The bathroom however was the worst of all, as the towels seemed to be old and rough. What topped us off was that the soap in the bathroom was left there for us to use from the previous guests - both in the shower and hand-basin. Assuming that this was an oversight, we discussed this with our friends staying there also and they had the same thing in their room. This is NOT good hygiene and is just being too tight.
Given that there are a few accommodation options along Moosstrasse, I would considered the other ones before staying here. Corners were cut in places that just should not have been.