I stayed for one month(November) while working out of an office in Gzira. It takes 10 minutes to walk down to the marina and another 15 minutes to walk along the harbour to Gzira. I mention it because the commute was really one of the highlights. Walking to Valletta is doable but takes 45 minutes.
The appartment is nice and airy and located in a relative new building. Noise from the neighbours and the street was limited. Much better than what I have experienced other places. There seems to be plenty of airconditions but I only used one of the aircon for heating a couple of days. The roundabout next to the appartment building is heavily trafficated day and night. You don't want to sit out on the balcony in that noise or even have the doors open. I guess it's not a big issue in the summer, when people close the doors anyway to run the aircondition.
I never met Jean but he was a super responsive and nice to communicate with.