We (5 adults) spent 7 days in this apartment/flat. It was our 3rd visit to Keswick.
The location can't be beat, although with it comes the sounds of "downtown" -- mainly from dozens of folks lined up for gelato at the restaurant downstairs and early morning (6 AM) delivery trucks.
Everything was pretty clean and comfortable, although we did find some remnants of earlier occupants on the bedroom floor -- dental floss picks, etc. Living room pillows were a bit grimy. Kitchen was modern and well equipped and everything worked well. Washer/dryer worked well, too.
While we knew when booking that the property was spread throughout several floors, we underestimated the amount of up/down movement we'd be doing, as the living room/kitchen is on theTOP floor. Even though we are very fit and active, it became a real drag to keep going up/down 3+ flights constantly, as the living area is at the top and the bedrooms are below -- the reverse of most multi-story houses (like our 3.5 story townhouse that we live in.)
Lastly, our main issue was that there is only a single window in the top floor living room/kitchen area. It was constantly hot and stuffy, despite opening nearly every window in the house and turning on a single fan. The back windows in the kitchen are fixed panes and act as a greenhouse -- super warm, even with the honeycomb blinds drawn. If a single one of those could be made into an awning window or skylight, it would make a huge difference!
Overall, not a bad place to stay for a couple nights but I wouldn't stay again for an entire week.