The Westin Prince is a nice enough property. It's situated on a fairly large piece of land which has been reasonably well landscaped to the point that it's almost park-like. The trouble is that once you leave the property, there's nothing there. It's not in a bad neighbourhood by any means; it's just that there's nothing of interest nearby unless you have a car and can drive to wherever.
Downtown (Sheraton Centre) is downtown so there's lots nearby within very easy walking distance. The lounge is quite nice though food / drink offerings are somewhat run-of-the-mill.
The Westin Harbour Castle will have nice views out over the lake (obviously weather dependent) but I've always thought of that particular location as being just 3 or so blocks away from actually being convenient for walking to / from places of interest. The streetcar service is right there though so you do have very easy access to the main public transit options.