This is a great apartment, and although it's expensive, it was absolutely worth it. The location is great, and you feel the sense of history. The owner was friendly and lived just across, which was convenient in case of questions.
The only nuisance: Check-in procedure was at least 10 pages, and the tone was not very welcoming (several rules with fines if keys got lost, automatic check-in would not succeed etc.). For this amount of money I would expect a smoother check-in process. Which is a shame, especially as the actual experience was perfect and the owner lived right across the apartment. So check-in should't be this difficult.
But nevertheless, we would certainly recommend booking this apartment! :)