I like both but I prefer the Metroidvania style!
Many years ago I saw in a TV show Castlevania (I didn't know the name that time) Symphony of the Night and Castlevania Harmony of Dissonance. From that moment I realised that those games are made for me
I mean huge Castle to explore, enemies from different mythologies, backtracking, progression, cool story - it is just too good.
I played all "RPG" Castlevania games on emulators (I am sorry about that) but 2 years ago I bought Nintendo DS lite and now I have CotM,HoD,AoS,DoS,PoR,OoE and I am happy to say that it is awesome to play them everywhere I want