I started messaging the hotel about some arrangements a couple of weeks prior to my arrival, and they were very responsive and helpful. The check-in staff misspelled a guest's name when applying for the digital Interlaken Guest Card, but when we followed up with another staff the next morning, she quickly resolved it by providing us with a physical card.
The hotel is conveniently located - only a few minutes' walk from the train station and very close to shops and restaurant. We left the windows opened a little during the night but it wasn't noisy. Although the hotel is old (built in 1800s apparently), there is an elevator and everything was clean. They probably realized that the rooms could be quite warm in warmer months, so a good sized standing fan was included in the room, which was perfect (perfect temperature in the night). The rain was heavy in the final night we stayed and the windows were dripping a little even though they were closed. We placed two small towels under the windows and it was okay.
Our booking included free breakfast. On the days we ate there, there were scrambled eggs, roasted potatoes, hams, yoghurts, bread, fruits, coffee, tea, juice, etc., which is pretty decent.
I saw the bad reviews before I booked and I was worried, but I did not experience any of those. In fact, I would recommend this hotel to anyone visiting Interlaken.