Kiseli Ada is my preferred anchorage in this area and a lovely place to spend a night or even two. If time is short, it also works perfectly for a quick swim. The sea colour here is beautiful, and the setting is attractive wherever you moor.
The main anchorage is quite small and can only accommodate a couple of boats. Behind the island, on the west side, there is another good mooring option with space for more boats. Just be aware that the northern end is shallower.
What I like most is the landscape, especially the stretch where the trees reach right down to the sea. That remains my favourite spot.
Practical Notes:
I do have some concerns about the future quality of the water. At the moment it remains acceptable, but the nearby fish farms make me cautious about how it may change over time.
One practical warning: some people say there are rats on the island. A common precaution is to cut a plastic bottle and place it around the mooring lines to help prevent unwanted visitors from coming aboard.