We really enjoyed our stay at Milos. The apartment was very clean, as it gets cleaned every day. There is also a comfy shower (not only a curtain), which we appreciated much after a long day at the beach.
Kalamaki itself provides many good tavernas, a bakery and a super market. The beach is reachable in 2mins by feet.
All in all we had relaxed days in Kalamaki and would definitely recommend the apartment!