As GOLD and DIAMOND, you are "Supposed" to get upgraded at checkin to best available for free. Of course it's up to the individual hotel even though it is published offically in the HHonours book.
One property I would NEVER NEVER return to is the new Vancouver Metrotown Hilton. I had to call the customer service agent and started a verbal fight with the front desk guy throwing rules back and forth at each other. They just refused to upgrade me to Exec. Floor even though it was almost empty. Eventually, the customer service agent apologize to me and inform the guy to upgrade me. It was just a foul experience.. I almost told the guy that I am going to check out right at that moment since I arrived before the cancel deadline.
On the other hand, the people at the Hilton Vancouver Airport is very nice. I have become almost a weekly guest at that hotel. Even though it is a all suite hotel, I always get the high floor corner room which is a bit bigger than all the others and most importantly respect from them!
This just proves how good customer service will keep our business.
Regards,
Empress