I stayed for two nights because of meetings in Slagelse. Although OnlySleep is efficiently located right at the motorway exit, the town center can be easily reached with a brisk 20-25 minute walk - or there's a bus stop right outside.
The room was OK and quite clean, but there was still rubbish, including an empty wine bottle, in the bin when I checked it.
Unfortunately, my the windows of my room faced east, so I woke up really early thanks to the sun shining through the thin curtains. That made it quite difficult to sleep enough. Blackout curtains would have made a world of difference.