I stayed in Deli Guesthouse for 11 days.
The location is great, very easy to get to the city centre on foot 15min walk - mainly steps which makes it quite difficult to get back (taxis are easy to find though) .
I also had my car so it was easy for me to move around.
The view is breathtaking, if it wasn’t for the windy days, I don’t think I would have left the house at all during my stay. Unfortunately, the veranda is not protected from the wind.
I was working from home, Wi-fi was good and reliable.
The only negative, is that there really is not parking on the premises (there are spots on the streets) but since I brought a lot of things with me it was very inconvenient carrying everything down to the house.
I communicated with Efi during my stay and she was very helpful.
Check in and check out were both flexible which was great and convenient for my arrival and departure.
I highly recommend Deli Guesthouse if visiting Syros island. The view itself is enough to enjoy your stay!