We stayed at the Caribe last August and had a very good time. Only real gripes were..
1. Some of the room blocks are very near the railway line and that can be quite noisy. However, the blocks at the other end of the resort are quite near the road, so I'd imagine it's quite difficult to escape some form of noise or other.
2. The outdoor dining area was very nice, but the staff seemed very slow to make up tables and we often ended up laying our own.
3. The hotels is rather less elegant than other 4 star's that we've stayed at, for example you are not shown to a table at dinner but have to find one yourself.
4. The sofa bed is a double, which our two boys (aged 5 & 7) hated. They usually get two singles elsewhere.
However food was good, staff are friendly and helpful, the deck area is lovely and the pools are great. The one with the completely sandy bottom is unique.
The hotel is the furthest from the park but they have a fairly regular road train, plus a bus service into central Salou.
Having said all that, we stayed at the Port Aventura back in 2002 and despite it's teething problems at the time (it had just opened) we preferred it. In particular the turnstile that takes you directly into the park is a real plus.