Pronounced El-pee-tha, although the d is a sort of combination d/th sound that can be hard for non-native speakers to get right. But if you don't speak Greek and you're trying to pronounce this name, El-pee-tha is a much better way than El-pee-da with a hard d.
90% a bad name in the ratings? Really? It isn't trashy or even illegitimate. It's pretty objectively decent, besides for how it sounds to some people (and it's silly to base just on sound). I think this is a cool name. The meaning is lovely and the sound/look is simple but distinct. It can fit with the "El-" trend, but still stand out.