What are you looking to eat? The other posters have already talked about the general old & worn feel of Penang, and I concur. The food is okay, but not as great as I was led to believe. I hazard that you can eat better in KL, and Sheraton Penang cannot compare to the KL hotels you mention.

Food-wise, KL is a haven as well, and taxis are much easier to get and cheaper than in Penang. If you stay at the Ritz - Jalan Bukit Bintang has got a number of places within walking distance for good hawker style food. One is the area near Swiss Garden Hotel with stands and small restaurants. Another is a place for Bah Kut Teh that is in the back around Marriot and Ritz. I was there long time ago, haven't gone of late but hear it is still there.

Chinatown is only about RM3 away by taxi for more eating places.

If you stay at Mandarin Oriental, you'll be right next to KLCC - which houses Suria Mall. Avoid the food courts there - food is really rather middling. Not as ideal a location for local chow, but the hotel is superb and highly recommended!