Motril actually consists of several different parts. You've got the town itself, the harbour (with its traditional fishermen district), the beach (many people live there all year round) and Playa Granada, a more exclusive part of beach where the King of Belgium has got his summer residence.
Motril offers excellent public health care, a hospital, public transport, Granada (and all the culture and monuments it offers) only 45 minutes away by car, Sierra Nevada if you like skiing, an international school in Almuñécar (19 km from Motril), good roads (except for the last few miles between Nerja and Motril, but next year that will be history), plenty of primary and secondary schools, shopping areas, the biggest beach in the province of Granada, an increasingly important harbour, etc. Basically, anything you may find in any other civilized place in the world, but better.
As for Playa Granada, the area where inmobiliaria-tropicalbeach is promoting off plan properties in a golf resort (5 min from Motril by car), it has grown considerably in the last few years, and many people live here all year round, but right now, apart from a good restaurant (just one), a five-star hotel (German) a golf course and a corner shop-type minisupermarket, you won't find anything else, but within four-five years you won't be able to recognize the place. There will be more four and five-star hotels, Playa Granada will have its own public primary and secondary schools, restaurants, golf courses, university buildings (the University of Granada plans to open an investigation centre here), a shopping centre, a medical centre, areas dedicated to different sports, etc. There will probably also be an international school here due to the high demand. One of the most ambitious projects in the area is Playagranadagolfresort (visit the website).
As you can see, what makes Playa Granada such an interesting place for investment is that it hasn't got everything yet, but the projects are there, so within only a few years this will be one of the most privileged areas in Spain. And due to the huge amount of golf resorts and public areas dedicated to sports and schools, this place will never be massified. That's why it's also a very attractive place for retirement.