I know the area well too as we have a place in Isla Plana. These are built by Mazalia I think. It is part of a mixed development of town houses, and front line luxury villas (custom built). The town council (Mazarron) have done a lot to spruce the area up and promote the town. The beaches are great. Airport is 45 minutes as Acer points out (San Javier). The town (Pueto Mazarron) has a very nice promenade and lots of restaurants. It is possible to walk into town from here.
At the nearby roundabout there are a few bars/restaurants, and the service station on the other roundabout does food, bread etc. I would question the theme park too, but all agents are saying it. When we started there was going to be a golf club nearby. So best to buy on the basis of what's there now.
I would recommend you look around. There are lot's to look at if you like the area. But do follow the advice given on this forum about LFO's, using independent legal advice etc.
I know of the agent, since we bought through a related company six years ago.
Hope this helps
Saludos