For my upcoming trip to Europe I've got two separate nights in Athens and I'm wondering what my best options are.

Situation 1

Arrive into ATH at 23:50. Probably a ferry (to Santorini) early in the morning the next day. I've currently booked us at the ATH Sofitel as it's reported to be literally across the street, but should I look at booking a hotel close to Piraeus instead? I've looked around and there doesn't seem to be any decent options, not to mention taxi after midnight is twice the price. The pro is convenient transit to hotel after arrival but con is probably will have to wake-up quite early.

Situation 2

Arrive into ATH from JTR at 07:50. We'll have the day in Athens and then a 09:30 flight to LHR the next day. I've booked us at the Athens Gate hotel but I wonder if maybe I should book us into the airport Sofitel instead? We can land, drop our bags, spend the day in the city, come back at night, wake-up "late" the next day and check-in for our flight.

As for the ferry question, if it comes down to booking a Blue Star Ferries from Athens to Santorini, is the cabin worth it? Considering it will be about a 7 hour trip that leaves at about 7 in the morning, a private room + bed might be nice. I can't seem to find any decent reviews/comments on the net on this topic.

Thanks all!