I didn't think much of the beach at Jimbaran. Lots of stones and not a place that I would be eager to go swimming. My personal view is the beach area has a dirty vibe to it. Saw rats in the planters 5 feet from where peeps were dining. Dining and drinking in the local shacks on the beach were almost priced on par with the LM.
Beach at Nusa Dua. When we were there you had to catch the tide at the right time or there was a long walk to be able to get into deep enough water to swim in. Not one of those beaches that everyone must see in their lifetime.