I often visit Sun Penang simply due to its location and the ambiance is great. However, the quality of the food is variable. Sometimes it's great, but other times the curry would be watered down or something disappointing like that. I would recommend the Sarong Burang though if you like yam--delicious, fun to say the name, but sort of expensive.
Overall, I don't feel like their price is appropriate for the quality of the food. I ate at Malaysian restaurants in Sunset Park part of Brookyln, and for a comparable dish that may only cost $5 in Brooklyn and tastes better, Sun Penang does not do as well.
Edit on 3/23/10:
After a visit here today, I feel like Sun Penang should now be downgraded to 1.5 stars. $11 for Tom Yum Soup without much seafood or ANY noodles! The man on the phone told me afterwards that it's usual for the soup to be without noodles. My reaction: What??! How much do I need to pay to get soup and noodles?