I stayed in Sheraton Poznan two nights in June 2014.
It is a nice hotel; good solid Sheraton standard is everywhere – spacious room, well equipped bathroom, breakfast with good variety of food in all categories etc. Professional front desk staff and fast check in/ check out.
It was a business trip and I also booked a small conference room in the hotel. This functioned well, although room itself was nothing special, with heavy and clumsy furniture. The price for 4 persons and 6 hours was 203 EUR, and this is definitely “high end” price category.
I would have been a satisfied guest, if not one irritating detail – I was asked to pay for wifi in the room! 80 Zl/19 EUR per day of use if wifi! Amazing! I was told, that, because I have booked a hotel room through hotels.com, free use of wifi in the room was not included. Somehow, free wifi is what you expect from a wel renowned 5 star hotel....
I will definitely choose another hotel for my next business trip to Poznan.