Manolis' apartment is amazing. The pictures don't do it justice. There is a front porch and balcony looking out over Santorini, and he has two bathrooms. We never met Manolis directly, but he kindly arranged a taxi to pick us up from the port and picking up the key from Penguin was not a problem at all.
Location is always the most important thing when looking for an Airbnb and Manolis' place did not disappoint. It is walking distance from everything you might want to see in Fira.
Overall, I would say this place is probably the nicest Airbnb in which I have stayed. I highly recommend it.