We have lived on Oahu for almost 6 years, I have been to Germaines about 10 times, I have been to Paradise Cove once. The reason....I think Germaines makes you feel more at home, more like an authentic luau. Paradise Cove is more commercialized. Seems like they are all about getting the money there. Germaines is smaller, more intimate. Germaines is on the beach...but it is rocky, and not accessible to the water. On that note, Paradise Cove does have a leg up....nicer beach. Drinks-Germaines has awsome drinks, they don't skimp on liquor. I think Paradise Cove just gives you fruit punch.
So, all that said, I prefer Germaines.