Super Castlevania 4 is my favorite for 16 bit mainly because of the OST. It nails the whole Vampire Hunter on a lonely and dark quest to nail Dracula aestethic perfectly. It had a classical music vibe, the way I like it best and I really like almost all the songs in the game. (The library song is the only one I didn't like)
I'd score Rondo higher but it always irritated me that you can't save everyone in one go for the best outcome. In that respect, Dracula X for the SNES satisfied that need. Also, I might have been irritated with Symphony of the Night's intro if I didn't play Dracula X beforehand since it was the only game I could access at that time that referred to Richter's victory so there's that for nostalgia.
I always thought Bloodlines was neat in the sense that it tried to tie Bram Stoker's novel with the franchise...at least before it was retconned.