A very nice place right in Gamla Stan. It's self-checkin, and the key can be left in a keybox also during your stay. That means that during your stay, you don't need to worry who has the key in your group. You can always enter the place. Very flexible and useful!
There are curtains to darken the windows, very useful in the summer. Even has a washing mashine.
Careful: not possible to leave bags after check-out.