We probably stayed here much longer than we should; eight days, although we were at a part of our journey where we didn't much want to pick up and move every other day, plus we wanted to learn as much about Mainz as possible. We did a lot of walking, visiting shops, doing laundry, etc.
As others have mentioned, Klaus is very engaging, speaking excellent English, plus he helped me work on my slowly advancing German skills. Uschi is less well versed in English, but she tries. The pair also operate the adjacent Specht restaurant in the evening. They also have a dog, Ambela, with whom we fell in love, but then we are dog people anyway. Klaus tried to keep her corralled occasionally, but for the most part she had free run of the hotel and the restaurant. Others might not be so willing to share their environment with her.
The beds were single beds, so my spouse and I had to sleep separately. They were actually better beds than a 3-inch mattress on a wood box (not a box spring) might lead you to believe.
The wifi in the room (3rd floor - equivalent to 4th floor for Americans) was EXTREMELY spotty. There were large spans of time when the signal in the room was non-existent. And very slow when the signal was present. Klaus tried to make apologies, and said that there were routers on each floor. Signal absence didn't really do much to make that an effective excuse. Fortunately (sort of) I discovered on the second day that sitting in the "lobby" there was an excellent, fast signal, so when I really REALLY needed to post some photos, I could go down there.
This was summer, at 50° North Latitude, so sunrise made the room bright by 5am (the windows and curtains were kept open to keep the room acceptably cool). Soon thereafter, workmen appeared. There was renovation being done in the platz on water, gas and electric lines, with the concomitant heavy equipment running. It didn't do much for our ability to sleep as late as we'd like, but that will be only a temporary condition. The platz is fully cobblestoned, so deliveries to nearby businesses, like the adjacent bar were being done by wood pallets on pallet jacks. A smooth surface would not have been a problem. Clattering on those cobblestones was quite noisy indeed, especially early in the morning.
As others have reported, we got the "Is it possible to pay in cash?" gambit on our next to last day. Hey, I get it. Credit card companies charge sometime exorbitant fees to process payments. At least we didn't get the "our machine is broken" sob story. We were dubious about being able to acquire so much cash on short notice, and told him so. Klaus tried to be a little more accommodating; Uschi seemed to be pushing him to be more insistent on cash payment. If we had known at the beginning of our stay, we might have been able to work it out. As it was, finding out on the day before checkout, it could not be done. We went to the GeldAutomat that morning, and came up with about a third of the bill. The rest had to be done on the card. Sorry, Klaus and Uschi. read more