Iota is completely different than current cryptocurrencies. It doesn't implement blockchain technology. It implements Tangle technology. With tangle, there's no mining, no fees. The transactions are instantaneous.

There are still nodes, yes, but there are no miners. The nodes are the ones that verify and process transactions by "tangling" with each other. In order for the current transaction to process, it must first verify 2 other transactions from two different nodes, so what you get is a web effect.

But ADA is still using traditional blockchain technology.