My wife, I and our 6 months old baby have spent here 5 days.
First of all - the studio is wonderful (exactly as on pictures) and location is perfect. All Oia's major signs and viewpoints just in a few steps above. Breakfasts and suppers on the balcony with peaceful view to caldera were amazing.
But one thing was spoiling our rest. The bed base was slatted but these slats were too short and unfixed - just have been laid across the bed. Periodically they shifted to the left or right side of the bed themselves and we fell down. Usually it was at night, while we were sleeping, but a few times the mattress fell down just when I sat down. So the bed base should be changed ASAP because it is unsafe.
Also you should be ready to have no internet access during several days. As I understand from previous feedbacks - it is a common situation here and may be in Oia as a whole (in our case the wires has been broken somewhere outside).
Everything else was perfect!