DoubleTree Warsaw is far newer and nicer property than any of the Blu's, but it's essentially in the middle of nowhere with not so easy to access by public transportation (though Uber is always an option). It has a nice lounge, great breakfast and weekend free shuttle to the citycenter (and back). Centrum is renovating rooms, but the progress is slow. Last time i was there, at least the 10th floor (all business class rooms) was fully renovated, with some rooms on lower floors renovated here and there. That may explain the nickle&dime attitude at Centrum - i'd assume renovation isn't cheap :-) Just kidding, Centrum was a great hotel not so long ago, at least staff-wise. It's sad your experience suggests it has changed...