Used the bus, took us to the Unter den Linden which was 5 minutes walk away. We got a 4 day transport pass at the airport & the bus was included. You need to validate your ticket on the bus.

If you are planning to use public transport during your stay, the Welcome Card is excellent value. Get one for zones ABC since Schönefeld is in zone C. We took the S-bahn S9 train from the airport station to Friedrichstraße station. The regional trains also do the same journey and stop less and are therefore slightly quicker. Just get on the first train that is going to central Berlin. Then on Friedrichstraße itself (just by the S-bahn station exits) get the 147 bus to Werderscher Markt (3rd stop) which is 2 mins walk from the hotel. You actually pass the hotel just before the stop. Note that Schönefeld airport station is a good 5-10 mins walk from the terminals. It is well signed. Otherwise the journey is easy, comfortable and in total takes 30-40 mins.

Yes to hair dryer and safe. No to iron. We requested one from housekeeping and they brought it up to us.