Are you talking about the Pullman Schweitzerhof ? If yes, this is an ex-Sofitel, quite nice and in a pleasant and convenient area. I stayed there 3 times (2 at the time it was a Sofitel and one under the Pullman brand). I didn't notice any big change with the change of brand. The rooms are not huge but they are nice and comfy.
Very good breakfast buffet. Restaurant for dinner a little bit pricey. Drink voucher is given (although I remember having sometimes to ask for it). Very professional staff (as usual in Germany).
Only negative point : I never received any upgrade.
Would I return there : certainly, without hesitation.