I travelled to Riu Costa Lago with 2 friends for a weeks break in the first week of July. The hotel is a 15/20 minute coach journey from the airport and less than a 5 minute walk down the road to the beach. On arrival, the reception staff laid on champagne and gave us all the information we needed for our room, safe, pool towels and dining times. You have to choose a time for dinner - either 6.30 or 8.30, but this can be changed if you're going out for the day or on a trip (they'll even give you a lunch box of fruit and water, which you can top up with food from the breakfast buffet). I would recommend taking the 6.30 sitting, as the lounge bar gets really crowded of an evening and it'll give you the opportunity to get a seat.
The rooms are dated, but they're perfectly clean and have plenty of storage. We were towards the front of the hotel, facing the road. I personally preferred this as we could see the sea and didn't have the noise of the pool/lounge bar of an evening. We did notice some rooms around the pool were on the ground floor facing the pool - they didn't have any privacy and I wouldn't have been happy in one of them!
The food was lovely, very varied with plenty of vegetables, salads and meats on offer. In the evening there's a cooking station where there's always some form of carvery meat, and fish is served every day. You can also get your bread and butter, chips, burgers, pasta etc. Breakfast offers a variety of eggs, bacon, sausage - all the usual favourites, as well as cereals, croissants and yoghurts.
The pool is smaller than expected, but I found we were able to get a few sunbeds up until about 10am. If there are a lot of you then I'd get down there early, as people do come down at 7 to put their towels on a bed and then go off to breakfast, returning at 10. The pool bar is behind the pool, with self-service wine, beer and soft drinks. The bar is staffed if you prefer spirits. This closes in the evening, with the lounge bar acting as its replacement. The only problem I found with this is that if you don't want to be around the pool you still have to go past it to get a drink from the pool bar in the day. Personally, I feel the hotel and guests would benefit from the lounge bar being open in the day, too, even if only for the self service machines. There's a lovely terrace by the lounge bar where you can sit if you can't get a sunbed!
Our group travelled during the World Cup, and so evenings were accompanied by a projection screen on the terrace showing the live matches. This refers back to my point about preferring a road-facing room as the guests become quite loud and of course the kids do scream a lot. The entertainment inside the bar was pretty standard of hotel-run entertainment. There were some Spanish dance acts, a kids' disco and entertainer, and a strange man playing the keyboard. Again, if you'd prefer to sit outside of an evening then go for the early dinner sitting and get yourself a table and chairs.
Outside of the hotel is a bus stop which can take you into Torremolinos centre, or up the road you'll find the train station which is best for trips to Benalmadena and Fuengiorola. That being said, Torremolinos is about a 30 minute walk form the hotel. Turn left out of the hotel, down the road to the beach, then turn right and just walk along the sands until you see the sign for the town centre. It's really not that far and there are lots of little shops to stop at on the way. Speaking of the beach, the sunbeds and parasols are chargeable - around 4 euros per day. We just bought those wicker mats for 2 euros and laid on them! Closer to home you'll find a small supermarket, lots of kiosks offering icecreams, crisps and drinks, the usual souvenier shops and a few bars and restaurants - lots of which are on the sandy beach with inspired barbecues made out of little boats (again left out of the hotel then right when you reach the beach).
Overall this is a nice hotel in a very good location where you can get the best everything - relaxation, shopping and bars. The staff are fantastic, they really aim to please and if you have any problems they're great at sorting it out. As an example, we needed an extra chair for the balcony. We asked in the morning, by the time we got back to our room to change for dinner the staff had put an extra chair on the balcony for us - as well as a towel-elephant :)