The beachfront rooms are all in buildings A and B only, that is the only room catergory in those buildings (A and B).
The one bedroom ocean suites are on up the cliffs spread out amongst the other remaining buildings.
The beachfront rooms are not ON the beach, but all the balconies face the beach (the lawn is between buildings A and B, and the beach). Whereas the ocean suite rooms are higher up and have the ocean views instead.
The beachfront rooms balconies are not as private since they are over the lawn facing the beach... but are very nice rooms and close to Pallazina, the beach, the beach grill, and SSB. The other rooms are higher up the cliffs and therefore have more steps to everything mentioned above, but are closer to the lobby, Balloon Bar, spa and Cassanova restaurant.
So after deciding where (location) you would like to be generally, then you can pick what room category you want.
I believe any room at CSS has its perfection and beauty, no matter which one you pick. We prefer the one bedroom ocean suite because we like the ocean views and a bit more privacy on the balcony.
The 1BR Ocean Suites are typically on the opposite side of the resort overlooking the bay/ocean from G and D block, closer to the Balloon Bar, spa, gym & mineral pool. The Beachfront Suites are located in A&B blocks, overlooking the main beach. Both room types are quite lovely and spacious. Your preference is likely to be determined by your priority of view (1br Ocean) vs. close proximity (Beachfront) to the beach/restaurants. I book the 1BR Ocean suites, but I like the walk to and from the beach to work off the fabulous food and we hit the gym every morning, which we did not do when we stayed in the beachfront suite. The beachfront suites are definitely more convenient to get more sunscreen, whatever you may have forgotten in your room to go to and from the beach/pool area. Either way, you can't go wrong! The pictures on the accommodations tab are very true to what you will experience at CSS. Have a great time and I hope this helps with your decisions!