Nano has no fees, and you don't have to wait for your transaction to be included in the next block. It also doesn't have the scalability limitations that all the traditional blockchain currencies have.
The tradeoff (read: downside) is, in order to keep the network secure, you have to either run a node 24/7 or trust your voting stake to someone who does (and there are many), so it's not as trustlessly decentralised as e.g. Bitcoin (not that Bitcoin is super decentralised these days).
But the no fees thing. It's really hard to embrace any currency with fees and delays, when you've played with something that doesn't have those things.