We only stayed for one night and it was comfortable. The place is far from Mykonos Town though. You still have to take the bus to the town. There is a bus stop just right in front and it takes 5-10 mins. If you're planning to go to town several times then also consider the bus fare. It's €1.80 per person per ride as of today.
It's also good to note that the listing is a guesthouse and there are several rooms for rent at Amaryllis. The photos are not exactly as what is in Airbnb especially the pool and jacuzzi setup. Probably because it's low season.