Stayed at the Ibis in September when I was in Berlin for a conference being held at the convention center directly across the street. I had my hesitations initially as I typically prefer to stay in 4+ star establishments especially when traveling in Europe but the Ibis was perfect. The room although small was clean and the service was friendly and accommodating. Breakfast was a bit expensive especially considering the the poor value of the USD but both the S and U-bahn were right outside the hotel door to make evening jaunts to downtown very convenient.

Opposite the Messe building, with excellent public transport connections (road connections too). The heart of Charlottenburg is just three S-Bahn stops away (Savignyplatz) with many restaurants in the side streets.

We arrived late and the receptionist was bored bordering on rude, but with a little tenacity we got all that we wanted (and what had been pre-arranged). The rooms are spacious and serve their purpose. The breakfast is well assorted and makes for a good start of the day.

We arrived early on the bus from Copenhagen exhausted, and the front desk person gave us a much earlier checkin than she had to. For that we will definitely stay at Ibis again (I'd never heard of them previously).