I steyed at Catherine's place with my friend for only two nights but we enjoyed it a lot. The flat is spacious - especially the kitchen area - and very clean, in fact, absolutely spotless! The place is in a quiet neighbourhood yet close to the main road (about 5 min walk) where you can catch a bus - it's especially well communicated with Valetta and Gozo island.
Catherine is a very fiendly and warm person, ready to help. On arrival she left us a 'welcome pack' - fruit, teas, coffee and other things, which was really sweet! She even printed boarding passes for us which was extremely helpful. I would recommend Catherine's place 100%.