A completely different structure from the original blockchain which requires…
A completely different structure from the original blockchain which requires no transaction fee.
Pros
It’s biggest selling point: no transaction fee. This makes micro-payment more feasible. This is realized by using a new concept called “Tangle”. Traditional miners are replaced by each network participant, which means you cannot mine IOTA and get rewards from doing it. Every participating blocks are required to verify two transactions in order to join the network.
Cons
No smart contracts in IOTA.
There will be no incentive for extra nodes to help verifying the transactions, as there will be zero reward for validating each transaction. That is, the network depends fully on its users.