We (Mum, Dad, 14yo son) spent a week here in late August and had a very enjoyable time.
The house was excellent - surprisingly spacious and very well fitted out, and the balcony with a sea view was perfect for sitting out during the day and in the evening.
Gioiosa Marea itself is a medium-sized town on the north coast of Sicily, a relatively straightforward drive or train ride from Palermo.
The beach is long and pebbly and not at all crowded, even in August, and of course being on the Mediterranean coast, the water is lovely and warm for swimming.
Although not the liveliest of resorts, there were several good places to sit out in the evening and get a drink and/or a pizza. Definitely recommended are the gelateria - ice cream shops - with wonderful ice cream and slush (known there as granita)
If you have the time, it's worth hiring a car and exploring inland (make sure you get a satnav or a decent map - ours was rubbish and we got lost on some VERY windy and steep roads)
Luigi could not have been more helpful before and during our stay. His father even picked us up on arrival from the railway station in his car and drove us up the steep hill to the house. Luigi popped in to check everything was ok (it was) and helped us to hire a car locally.
Only caveat is the walk back from the beach is very steep. Anyone with physical difficulties would require a car.
In summary, definitely recommended for families or small groups who want to avoid the noisier and livelier resorts.