Highly recommend Alex and Maria's place! It's in an excellent location - Kolonaki is the high-end neighborhood of Athens - and is very safe. It's about a 10-15 minute walk to Syntagma Square, 20 minute walk to Monastiraki, and about 30 minute walk to the Acropolis ticket booth, all enjoyable walks. It's also close to so many restaurants and shops. The interior of the studio is very nicely decorated, with all of the amenities you'll need. Alex was incredibly responsive with all communication, regularly checking in to make sure we had everything we needed. My friend arrived earlier than the check-in time, and they very easily accommodated an earlier check-in as there was no one staying the night before. Also, there was a ferry strike that ended up unexpectedly prolonging our stay in Athens, and Alex called me to make sure that we were doing okay, and easily arranged for us to stay at their place for a couple more nights. I absolutely recommend staying here; if I'm ever in Athens again this is where I'll be staying!