On a free weekend, I would select the Sheraton Centre over the Four Points Centre Ville [Downtown], just because it is a higher category property. It is at the higher end of the U.S. Sheraton quality scale, which can indeed be quite variable [as can domestic Hiltons]. It ranks with your average Westin. That said, I have found the Four Points both convenient and quite affordable, and stay there quite regularly when the budget is of concern. I have never experienced the type of incompitence alluded to by moeman. Just don't expect Westin-like standards and finishes. If you are travelling with children, it may be more convenient than the Sheraton, since you will find McGill University campus just down Sherbrooke, and kids would likely enjoy the green space and climb up the mountain. There is also a large grocery store around the other corner, at Park, which can help cater to the younger appetite.