The Guest House Heidelberg is in my mind akin to staying in a Best Western in the states. It's…read moresafe, and clean enough, but it's nothing to write home about and feels a bit dated.
All of that being said there were some things to love about this place:
1. The staff was some of the best we encountered in Germany. Very friendly and accomodating. Even was able to check us in early with no problems at all.
2. It's very walkable to the old town part of Heidelberg
3. It was very affordable while still being comfortable
As long as you set your expectations right this will be a pleasant stay for you.