Hello Fredrico,
This was my first JY holiday, so was quaking for a few months before, but I loved every minute of it.  Like other JY holidays I have been on the group gelled really well. 
The hotel is in a great location up on the hill overlooking the sea. The bedrooms are as you would expect in a Spanish hotel and not to everyone's taste but I found mine to be comfortable for the amount of time I spent in it! The pool area after a busy sightseeing day was a real bonus. The tours were very good and it is really up to yourself if you go on the optional ones or not.  Mijas itself is a pretty town, especially after all the day trippers have left! It is only a short walk along to the centre where there are lots of little cafes and bars. 
There is a bus service from just outside the hotel that takes you to Fuengirola where you can get trains or buses to other places nearby if you want to do that on a free day.
I hope this helps a bit.
Rae