Sanur is an upmarket alternative to Kuta for those coming to Bali for sea, sand and sun, and down-market alternative to Nusa Dua for those who want a package tour holiday in an air conditioned hotel with a swimming pool. There are some cheap pleaces to stay, as well as some good restaurant, so you don't have to swallow the high price at hotel restaurant.
The beach is pleasent and shetered by a reef. At low tide it's very shallow and you have to pick your way out over rocks and coral through knee-deep water. At high tide the swimming is fine and there is an array of water sports on offer- windsurfing, snorkelling, water-skiing, parasailling, paddle board etc.