I was looking for a nice clean budget hotel with ensuite rooms and good public transport connections. At the Platon hotel that is exactly what I found, in fact it was little better than expected. Maybe if I had seen the previous review I would have hesitated, even though it is a little old. However, I booked on Booking.com and based my choice on the reviews there, (you can only leave a review if you have actually stayed there).
The room was very clean and the sheets and towels were changed regularly. We chose to book without breakfast so I can't know what that was like. Room service prices for drinks were very reasonable. Staff were very helpfull and they even gave us a bottle of wine as a gift on New Year's Eve, (they did to all the guests). Great location by the sea but was well connected to the centre by 3 kinds of public transport that had stops just outside the hotel, (bus, trolley bus and tram) and the metro system was just two stops away. In fact, we were able to arrive at the hotel using the airport bus (got off at the metro station and then got the 40 bus direction Athens for three stops).
To get around Athens we used the weekly ticket which costs only 10 euro and gives unlimited travel on all normal public transport for 7 days. Speaking of public transport, we even got the public transport sightseeing bus, (N° 400). It cost only 5 euro and did the same route as the private sightseeing bus which cost 18 euro. The public bus ticket was valid for 24 hours, hop on, hop off, too and what's more, was valid on the other public transport during those 24 hours.

This is the worst hotel I've ever stayed in. I've stayed there 3 times in total, because it is close to a big congress center which organises fairs (EKEP). The staff are too unfriendly and rude. Everybody smokes everywhere in the hotel and it smells terrible. The first time I stayed there they damaged my suitcase and stole my money. The last time they lost my identity card in the reception and they said that I was responsible for it, not them. The rooms are pretty small in size and the breakfast is ok, but there is no place for no-smokers in the breakfast room and we were obliged to smell smoke while having breakfast.