I stayed for a conference in the adjoining Congress Centre - a late check-in was quick and efficient and throughout my stay the staff were without exception responsive and helpful.
The room was comfortable and whilst I didn't really suffer from excessive heat, I can see why some people have cited this as an issue. I tried to leave my window open several times and every time a gust of wind would force it shut!
I had a problem with the room safe early on morning and someone arrived at the room within minutes of my request for assistance and resolved the issue easily.
The only area for improvement (from a conference-goer's perspective) would be in the bar area - the bar is very small and service, whilst friendly, was somewhat slow. Given the common habits of conference-goers, a larger bar with a quicker turnaround would surely be a money-spinner.
So overall, if I were at the Congress Centre again, I'd definitely stay here.