The Sheraton is not all that downtrodden. It's location is ideal (across from City Hall and close to Yonge St. and the Eaton Centre). If you can manage Club Level, I'm sure you'll be satisfied. It is not a luxury collection but rather more of a business-oriented hotel.
The Westin Harbour Castle is prettier, but being on the lakefront, it's a little further from the hospital than you might like.