Vampire Savior was never released to the US on Saturn, but there is a secret option menu that allows you to change everything to English. Unfortunately, this also included the English censoring of blood to milk, but the option makes the game even more import friendly. (Plus, its really cheap if you look in the right places! I got my copy for less than $10.)
I honestly haven't played the PSX version, but from what I have heard, the load times are awful in the PSX version and they had to cut some frames of animation, but they try to make up for it by having unlockable artwork and customizable character palettes. The Saturn version makes no sacrifice, and there is only one loading screen the entire game (right when you boot the game up). For all purposes, the Saturn Vampire Savior is the best DS game to be made for consoles, with the possible exception of Chronicles for the PSP which I have not played (Chronicles for DC was kinda disappointing, I don't know how Capcom screwed up so much on the sprite and animation quality. It just didn't have the impact that VS did.)