Gwennoline’s place was conveniently located right in Valletta. It was a two minute walk from a grocery store and in the midst of endless restaurants/bars.
The place was clean and well equipped - There is also an elevator if needed to get up to the apartment.
There are busy restaurants on the street right below which is pretty loud until about midnight but the city seems to go silent after that time (at least when we went in November). This didn't bother us at all but I could see it being an issue for some.
I would highly recommend Gwennoline's place. She and her staff were responsive with any issues we had (AC and TV) and flexible with our check-in. The location was amazing and had everything you needed for short or longer stays (we stayed two weeks).