The major difference that is worth mentioning (apart from the DAG vs. Blockchain) is how IOTA achieves consensus and how transactions are made. As mentioned previously, there are no miners. What this means is that each participant in the network that wants to make a transaction has to actively participate in the consensus of the network by approving 2 past transactions. This attestation on the validity of two past transactions ensures that the whole network achieves consensus on the current state of approved transactions, and it enables a variety of unique features that are only seen in IOTA.
IOTA is the missing puzzle piece for the Machine Economy to fully emerge and reach its desired potential. We envision IOTA to be the public, permissionless backbone for the Internet of Things that enables true interoperability between all devices.