The location of the Mercury Residence is very good, in a quiet and nice urban area.
The apartment (very basic rooms indeed) was spacious and clean, there were also a lot of clean towels. Kitchen was well equipped. Balcony was very narrow, but useful. There was a laundromate too, which we didn't use though. Free wi-fi access in the apartment was a big advantage for us.

As I said, Mercury is in very good location, within only a few minutes walk to the Sliema - St Julian promenade, where bus stops are located. In the other direction, in 10-15 minutes one can walk to the Sliema seafront to catch the ferry boat from Sliema to Valletta for just 1€. Near the strand there's a large Tower Supermarket located.

All in all, If you're not looking for luxuries, but for a clean, basic apartment in a good location for a reasonable price, it's worth to consider staying in the Mercury Residence.

A few minor flaws:
- our balcony doors didn't close properly, and mosquitos were a serious problem.
- the archaic elevator begs for renovation, actually we prefered to use stairs instead of it.
- the check-in procedure might be sometimes complicated, as there's no reception in the Mercury Residence. We came on Sunday and had to use transport arranged by the hotel (the driver gave us a key to the apartment), which is admittedly very convenient, but not quite cheap (20€) in comparison to the public transport.