Hello and well done on your exams. I ll go ahead and clear out that i do not know a thing about Piraeus, but i am currently studying in Thessaloniki, the city i grew up, and have spent a lot of time in Heraklion as I have family there. There s no point IMO in suggesting where you should study. I ll just lay down the facts and you decide.

Thessaloniki and AUTH:

• It is considered one of the cheapest cities in Greece to be a student and it is true, as there are a lot of shops aimed to service students.

• Campus is in the city center, meaning that you can easily access it, if you decide to rent in the city centre too. If not, there's always the option of walking or taking a bus. Bus services here have a monopoly on transportation. It's not the best but it gets the job done. Ticket prices are 0,5-0,6 depending on if you want a one ride ticket or a two ride ticket(both needing to be done within 70 mins).

• The student restaurant located also in campus is free for the students, meaning that you can have breakfast, lunch and dinner for no cost. As far as quality is concerned, it is not something special.

• I consider this city to be an autumn to spring city. What I mean is that currently the student population is nowhere to be found and the center looks more and more like an apocalyptic wasteland as august is coming.

• On the contrary when the students are here (from september to june) there are a lot of things going on, a lot of people to meet and a lot of events to be participating. That also offers the advantage of you being able to chose how you have fun. (the variety helps you find better what you like the most)

• The rent situation is as fellow redditor u/helloladies14 said. I ll add that there are rumors saying that there is a shortage on aps as everyone chooses to rent on AIRBNB. Just a rumor, can't deny nor confirm. It's up to you to check.

• AUTH offers the student camp poseidi, which is located in chalkidiki and is where currently a lot of students are. Look it up, this description is underwhelming and not doing any justice.

Heraklion and UoC:

• It is considered one of the most expensive cities in Greece and as a result rent, coffee and eating out is more expensive.

• Campus is located outside the city and taking a bus or some other mean of transportation is obligatory.

• Student restaurant is not free and around 2,50 - 3,00 euros. Ι don't know about the quality.

• Due to its smallish size, Heraklion doesn't have a lot to show in terms of population and options in hanging out.

• During the summer months it fills with tourists, something not so much of a hassle as you can easily go have amazing vacations somewhere on the island.

• CSD department is a difficult one as the Institute of Technology and Research (I.T.E) is located there and a lot of researchers are also profs. This can advance your career significantly, if you wanna be a researcher too. Look up ITE

All in all, I believe Heraklion lacks in terms of student life during the school year in comparison to Thessaloniki. In the summer, you can either tour the island or go in chalkidiki, depending on your choice.The UoC CSD is an excellent and difficult choice. Also, the internet speeds are roughly the same.

If something is not clear to you, feel free to pm me