There is nothing wrong with the Sheraton. It is right on the 16th Street Mall, and in easy walking distance of the main downtown attractions (museums, sports arenas, state buildings, LoDo). The rooms are secure, and reasonably comfortable and quiet.
That being said, this hotel is not special. There are no robes or slippers for the average guest (The desk staff said there are some available, but they never did bring us any, despite our many requests). The pool is outside and heated, but there is not hot tub. There is a sauna and a decent exercise room with bikes and treadmills. It is in the tower building and a very long walk from the plaza building.
The food prices are very high, and you have to pay $10/day for a fridge. You also have to pay to use the ethernet in your room (about $20 for high speed daily, 11 for low speed daily). There is free wireless in the lobby.
In our room the showerhead was very poor and sprayed everywhere. The bathroom sink did not drain properly and "chugged" all the time (very annoying).
There was no ventilation in the room apart from the fan under the windows.
The bedcovers are the old-fashioned polyester kind that probably have never been washed. Expect to feel a bit germaphobic while here.
Bottom line: this is an okay hotel to be based out of, in a reasonable location. HOWEVER, it is not a good hotel for spending much time in. The average guest room does not offer robes, slippers, fresh air, a good shower, or clean-feeling linens.