It really is subjective, whether Symphony is the best. I love Symphony personally, and occasionally replay it from time to time as with most Castlevania games. The one that impressed me most however, with its mood and aesthetics, and often matching music, was Super Castlevania IV. I just love the level design, and for it being one of the "oldschool" Castlevania's, it does what it does as well as possible gameplay-wise, and mood-wise. It's dark and creepy, just like any Castlevania should be. So in my mind, it's the best.