Great place to stay at. Highly recommended. Fast/ immediate/ thorough responses from Vaki and Mike. Extremely safe residential area. Clean room. Comfortable bed. Well equipped apartment. It only takes about 20 Minutes to walk to syntagma and 25 minutes back (slightly uphill - good exercise though).
If you decide to stay here, I suggest the coffee shop "Le Petit", the owner there is super friendly and English friendly. The bakery shop Attica is also a nice place to grab a quick pastry.
Tip: It should only take 5€ Or less to get a taxi from syntagma square to the place.... if they ask for 20€, move on to the next taxi. I decided to walk with a suitcase and heavy backpack in toll.... don't do it. Unless you don't mind sweating.
And for data, don't go to Cosmote, it's expensive. Go across from cosmote in syntagma square and you can get a 3.5€ SIM card with 4.5g data at kapa exchange. So far, it's been working really well for me. Great coverage in Athens. I sometimes lose connection on the islands, but for the most part, it has been working swell for me.