If you require "hotel service" - this is a wrong door. go downhill and look for ***-hotels there.
If you are young at heart and If roof&bed are the only things you need on your vacation then this is the best option! extreamily cheap for such a well-known rich place, as Marbella is. Location is perfect: just between the city beach (700m downhill) and the bus-station (400m uphill), just above the downtown, and close to groccery store (across the road) and the japanese garden.
visitors are different: multilingva youth from all around the globe, eldery, sometimes kids (schoolgroups)
very cooperative personell: normally you reserve beds, not rooms, but we called by the phone in advance, and asked them about 1 room for two of us, and they provided one! we were lucky! they also gave us good advises where to go and what to see. (granada, malaga reachable by bus) all of them spoke good english, and one even spoke Russian!
bonuses: good food in the canteen, swimming pool, personal lockers.
no air condition: was not needed, nights were cool, and at noon we were never in.
minuses: common bathrooms, thin doors -- but that is _always_ like that in _hostels_.