Don't purchase the PSOne classic of SotN on the Vita, that'd be a bad choice.  Instead you should purchase Dracula X Chronicles(also available on the Vita.) 

Dracula X Chronicles is a remake of Rondo of Blood, better than RoB imo with the changes that's made.  It includes the remake, but also Symphony of  the Night, Rondo of Blood, and a game that was playable if you didn't have the right system card to play RoB.  Symphony of the Night included in Dracula X Chronicles includes redone voice acting, and while it no longer has the cheesy opening dialogue because of it, it's overall better.  It also includes Maria playable for the first time unless you count the NitM Maria on Saturn who really played nothing like Maria.  There are also extra weapons you can get, and you can now get the Axe Lord Armor in the regular game. 

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If you do choose to get a DS Castlevania, I'd recommend Dawn of Sorrow.  Dracula X Chronicles is the better game as it is an overall better package including three games instead of one, all three being some of the best in the series.  Dawn of Sorrow and Symphony of the Night are just as good as one another imo.  I will say that I've played SotN a large number of times that my opinion on it is less than it would be if I didn't play it as much.  It was one of those games that I replayed it over and over again the first time I played it, found out everything about the game and got kind of burnt out on it.  I know everything about the game backwards and forwards and I think that kind of degrades my opinion of it in a way. 

I prefer the sci-fi setting over the "gothic" setting, even though SotN is also fantastic. Plus, Super Metroid just has a VASTLY superior atmosphere and immersion.

Super Metroid is the better game. But SOTN is very good in it's on way!

I feel Circle of the Moon is the best "metroidvania" title. In my opinion it's the only one that could "rival" Super Metroid.

Wow, thanks for the info!! So I'm gonna get the Dracula X Chronicles

Symphony of the night in my opinion is the ultimate metroidvania game, but I to realize it wouldn´t be as good if games like Super Metroid didn´t exist.

Both games are amazing, but SoTN wins this one because Super Metroid is not my favorite Metroid game.

Just want to let you know that Symphony of the Night, Rondo of Blood, and Rondo of Blood Peke don't start out unlocked though.  If you play through the game thorougly though they're actually easy to get.

In the remake there are areas where you can find unlockables.  Most unlockables are hidden rocks that you break away, but SotN is in a gravestone at the end of the alternate stage three.  You need a subweapon like the axe, dagger, or cut down a platform held up by vines to get to the top section.  Rondo of Blood is on stage four.  If you get to the boss room, just don't go in, go back down stairs and hit the wall to the right to open up another path.  It's past that pathway in a candle at the top of some platforms.

The developers wanted people to play through the game and unlock them rather than just starting the games off as playable.

Symphony of the Night, no question. Still has yet to be surpassed in the metroidvania genre.

Super Metroid IMO. I dunno, just facing a boss that was 2 screens big (no exaggeration), bosses that wouldn't show up for like 15-20 seconds, then barrage you with attacks suddenly in the air, plus the whole Alien movie atmosphere really made Super Metroid stick out for me.

SotN was no flop though. I remember it being ranked higher in some gaming magazines for game of the year than FFVII, and that's saying a lot!! Plus it's soundtrack is so B.A.D.A.S.S!! I still listen to some of it's toons to this day.

They should have ported the OG to the DS!!

Super Metroid for me