We had a great stay in Pasquale's apartment in Mattinata.
Apartment: it was clean and exactly as seen on the pictures. Giant terrace with a magnificent view over the olive groves and the Mediterranean Sea that was shady in the late afternoon. Bed was fine for a couple of days. The shower would be better with a tray. Free parking in front of the house (but it needed some practice for me).
Host: Pasquale was super friendly and attentive. Every morning, he made excellent fresh coffee and delicious breakfast with juice, marmelade, eggs etc.
Vicinities: beach in Mattinata was okay for a short cooling. Better check out for Mergoli, Mattinatella or Vignanotica. Also you can reach Vieste or Monte Sant'Angelo by car easily.
Mattinata: Is a small but nice town that gets alive in the evening. There are some nice restaurants at the sea which you can access by car (e.g., Dalla Nonna) and many nice bars and restos in the pedestrian area at Corso Martino within walking distance (e.g., La Vineria or De Gustibus).