Although it hasn't been updated for almost two years (and probably won't since if I remember correctly Sony bought the rights from Connectix), I think that this emulator remains the best for 2-D PS games.
ePSXe is far more superior for everything else. But I always had a better experience playing Castlevania SOTN/NITM on VGS than on ePSXe. No matter the settings, ePSXe gives me choppy screen transitions and the music sometimes becomes jungle techno for a few seconds.
Anyway, as there are some good memory cards converting tools, the time played to test VGS won't be wasted in vain.