I booked the flat for 2 days in October 2014 and the experience was great. Christ kept in touch during the time before the check in, reassuring me everything is according to plan. The actual check in went smoothly, Chris was there right at the agreed time to help us settle in and made sure everything was to our liking before leaving.
The apartment is indeed the best location in Zurich. Very central (6 minute walk from the main train station) in the old town with a wonderful view of the river and the other bank. It is pretty small and cosy, and was clean and prepared for our arrival. The check out also went as good as it could. Would definitely recommend.