The Flying Saucer is all the rage.
Great for family fun and 1-5 children can use it at once.
An observation we have made with this type of swing is that because it accommodates so many children it gets very heavy, and we have had a close call with a toddler running around, so like on all playgrounds be careful.
On Places.NZ site this type of swing is also described as a Swing Basket.