We stayed at the Sol Azur couple of years ago. The first couple of days were spent at the Royal Azur because of over booking at the Sol Azur. From what I can remember the bedrooms had very similar decor - though the room in Sol Azur was a lot lighter and had a balcony and that in Royal Azur hadn't. Its possible though that as we were only going to be there 2 days that they gave us the least desirable rooms in Royal Azur. The (separate) loo in the Royal Azur leaked slightly.

The public rooms were slightly plusher in The Royal but I preferred the restaurant in the Sol. Drink prices were higher in the Royal than in the Sol with the exception of the red wine at dinner.

The outdoor swimming pool at the Royal had a water chute (be careful as you come down as people slipped all over the place). As you walk down to the beach there are several sunbathing terraces. Both pools offered waiter service and beach towels.

Technically you can use the facilities of all the hotels in the group - the 2 hotels are separated by the 3* Bel Azur - but in practice not always. Having moved from one hotel to another we went back to the Royal to sunbathe and were asked by a pool boy who didn't recognise us for our room number. There is absolutely no problem using the other hotels for evening entertainment. The Bel Azur has a lovely restaurant where we lunched outside overlooking the sea.

The beach area at the Royal was narrower and stonier at the Royal than at the Sol. Both provided beach loungers and free towels.

I would be happy to stay at either of the hotels again but would not wish to pay a large premium to stay at the Royal. Although the service was good if you are expecting a luxurious 5* hotel you will be disappointed!

Hope this information helps!
Caro