We are a family with two schoolkids. We had a great stay in Marina in August 2021. The apartment is exactly as described, the instructions are sent beforehand and are clear, check in / check out is easy and fast (via key locker with code). Apartment is clean and spacious and has a nice view to Marina from three sides (unfortunately no lake view, but it's not a problem). On a sunny day the whole apartment is filled with sunlight throughout the day. Despite the fact that many apartments are occupied Marina is very quite, you hardly hear anything besides quacking of ducks.
The communication with Sterlin was prompt and our requests were fulfilled very quickly. The presence of microwave and washer/drier was very convenient. Special thanks from me for a collection of books about Switzerland which I wanted to read for a long time. Unfortunately I didn't have time to read them all because there was so much to do around (lake, trains park, water park etc), so I would be happy to stay there again next time to finish reading.
I highly recommend this apartment to everybody.