Had a short stay here last week.
As a newly-matched Plat with little Bonvoy history, I was satisfied. Room was "upgraded" from Standard to club room. But club room was fine, still sort of modern/fresh except for the tub (no rainshower) in the bathroom.
Location is a bit outside the old town but with excellent, cheap public transport options (to the Old Town as well as the airport) right outside the hotel. For those on business stays, you would be right next to the trade fair and fairly close to the central train station and several banks.
Breakfast in the restaurant was pretty good. Although, breakfast is usually quite good in upscale hotels in Poland. Thus, relatively speaking, it was not exceptional. For the other meals of the day, I am not the biggest fan of Polish cuisine. Too heavy and too much meat for me. So I did not check out the restaurant or the lounge during happy hour (6 PM to 8 PM). But I stopped by the lounge during the morning and the afternoon. Very basic offering. Good for a coffee, a water, a coke, or a cookie, but nothing I would pay for if it was not free as Platinum.
Overall, do not expect something exceptional but personally, I had no pressure points at all and would certainly recommend this hotel. Keep in mind it is Poznan, you do not have the alternatives you would have in Vienna, Budapest, or Prague.