I went to Enforex a few years ago - highly recommend it, especially for the socialising point of view - lots of partying and drunkeness. Most people are aged 18 - 23 - with a few older ones like myself!! but I still managed to keep up with the younger ones!!! There are people from all countries - mainly scandinavians, english, irish, american and german - get the odd eastern european and russian.
Generally life consists of school in the morning (if you can be bothered), then straight to the beach (from april onwards), head home around 6, relax and decide what the plan is for the night, then either hit Party Banus or a night in the old town in Marbella!! and repeat!! it's a hard life
As for the actual learning side of things - school is good, small size classes and the teachers are young and friendly, no real pressure to go to school if you don't feel like it - hungover etc!!
I would recommend getting a shared self catering apartment, unless you really really wanna study hard - then try and stay with a family - but can be a bit if a gamble - can end up being in a apartment with an old spanish lady who is only interested in receiving rent money rather than helping you improve your Spanish.
Hope you find my advice worthy!!