I wouldn't spend points for an upgrade, but if you are Gold you should always get one of the nicest rooms in the hotel that is not Club level or a full suite. Out of 17 stays this year the only time I have not been upgraded is at Four Points (budget hotel, not a lot of service).

If you are Platinum you should be upgraded to a Club Floor room or a suite most every time.

Make sure your SPG number is in the reservation, then ask again at the front desk if necessary (I have not found it necessary).