My ex and I went to Aghios Gordios in August 2002, with Kosmar. The resort was absolutely fabulous in our opinion, but you're interested in the apartments.
Marinella was fine. It is up a fairly steep slope, but not at all far from the town. It was clean and in good order, and also quiet. Not exactly a haunt for ravers, but then Aghios Gordios isn't that kind of place.
My girlfriend did suffer trying to sleep in the heat at night, being paranoid about keeping the patio doors open for fear of mosquitos. I discovered that a large fan could be hired from the supermarket on the roundabout (you'll know when you get there) for a pittance and problem was solved.
Marinella does not have a pool, which personally I prefer - I don't want poolside noise if I am trying to relax in my apartment. There are ample pools to try out within easy walking distance, go find them!
It was great apartments apart from the steep hill you have to walk up but its even worse getting your cases up the hill.