I have stayed there twice as SPG Gold but have never been upgraded ( eventhough they told me that my room is on a very "special" floor called "SPG Floor" !!)
Dont be deceived by the pictures on the website. The rooms are very simple and the furnitures look more like something from a furniture reject centre ! However, the hotel is reasonably clean and for the price, yes its fairly good value for money.
If you are going to stay at Pangkor Laut prior to your Penang trip, I dont think its a good idea to stay at the Sheraton. The contrast is just too great and may ruin your holiday mood. My suggestion for Penang would be E&O which seems nice and pretty upmarket (although I have not stayed there before).