tasty, interesting, and affordable. as others here have mentioned the choices for malaysian food, even in a city the size of l.a. , are limited. i have tired the 5 or 6 others in the area and penang comes in as my favorite. i have also visited the penang in ny, philly, and atlanta. i believe they are all related in some way although they differ quite a bit in atmosphere.
penang in covina is slightly hidden away in the corner of a decent shopping center with lots of free parking. the atmosphere is casual and no reservations are required. even on a weekend one can expect to be seated immediately.
the food is mostly very good. the roti canai is crispy and hot just like one from a hawker center in kl. the curry dipping sauce is also real malaysian curry flavor (although not as spicy as in malaysia). thesatayis good to very-good as well. not as good as in malaysia but better than the thai or indonesian varieties other restaurants try and pass off as malaysian satay. the rendang is as good as or better than any other in the l.a. area. he soups in general have the hot and sour flavors one expects, although the chili is toned down a bit from malaysia. as others mentioned the one area they fall short is seafood. its not super sweet and fresh.
prices are very affordable as well. they have new lunch specials which are down right cheap and dinner is on the mid-low end.
just fyi there is also an indonesian food court several doors down from penang but in the same shopping center. i couldn't find a listing for them on urban spoon but they are certainly worth a try as well and have some hidden gems.