It is small and private. The sand is not soft and white like at Negril, but it is a fine beach as long as you don't compare it to the Negril beaches. The resort has only 150 rooms, so it is never crowded. There is plenty of shade and the water is crystal clear. There is some seaweed in the water, but it is easy to step over if you don't want to step on it. You don't need water shoes.
It's a small beach so if you want long walks on the beach, you won't get that. The water was pretty warm. We went in with no shoes and floated around on our floaties from the chairs. There's not much shade unless you get one of the huts to shade you. There are some trees off to one side and if you get close enough to those you can get a little shade.
The sea bottom at CSS has some seagrass and can be a little mucky compared to CSA/CN. However, I actually enjoyed the sea grass since it was cool to see fish swimming around the seagrass. If you don't like a slightly mucky bottom, you might want to bring water shoes. Also, if you plan to walk out to the right of the cliffs, it can get a little rocky (this area is outside of the roped off area).
The beach is small, but it never seemed crowded to us, and we absolutely never had a problem finding lounges, chairs, or shade.
Funny, but no one reported on the beach on the SSB side of CSS. There are both trees and Palapas to provide shade. Water shoes definitly help over there, because the bottom has some larger rocks due to the river that flow past it. We managed to get in without them, we just hopped on the lounge floats that much faster. Where we found water shoes to be needed was in the pool at SSB. It has a rough texture and our feet got scraped up during some impromptu volleyball sessions.
Sunset Beach in the Rain
This is a view of the beach in the rain at SSB. You can really see how the White River cuts into the beach area in this shot. Normally the beach extends to where the sand bars are.